is it too late for me to be GM

Possibly of interest:
"... the NM title is an honor that only one percent of USCF members attain. ..." - IM John Donaldson (2015)
http://www.jeremysilman.com/shop/pc/Reaching-the-Top-77p3905.htm
What It Takes to Become a Chess Master by Andrew Soltis
"... going from good at tactics to great at tactics ... doesn't translate into much greater strength. ... You need a relatively good memory to reach average strength. But a much better memory isn't going to make you a master. ... there's a powerful law of diminishing returns in chess calculation, ... Your rating may have been steadily rising when suddenly it stops. ... One explanation for the wall is that most players got to where they are by learning how to not lose. ... Mastering chess ... requires a new set of skills and traits. ... Many of these attributes are kinds of know-how, such as understanding when to change the pawn structure or what a positionally won game looks like and how to deal with it. Some are habits, like always looking for targets. Others are refined senses, like recognizing a critical middlegame moment or feeling when time is on your side and when it isn't. ..." - GM Andrew Soltis (2012)
https://web.archive.org/web/20140708093409/http://www.chesscafe.com/text/review857.pdf
100 Chess Master Trade Secrets by Andrew Soltis
https://web.archive.org/web/20140708094523/http://www.chesscafe.com/text/review916.pdf
Reaching the Top?! by Peter Kurzdorfer
"... On the one hand, your play needs to be purposeful much of the time; the ability to navigate through many different types of positions needs to be yours; your ability to calculate variations and find candidate moves needs to be present in at least an embryonic stage. On the other hand, it will be heart-warming and perhaps inspiring to realize that you do not need to give up blunders or misconceptions or a poor memory or sloppy calculating habits; that you do not need to know all the latest opening variations, or even know what they are called. You do not have to memorize hundreds of endgame positions or instantly recognize the proper procedure in a variety of pawn structures.
[To play at a master level consistently] is not an easy task, to be sure ..., but it is a possible one. ..." - NM Peter Kurzdorfer (2015)
http://www.thechessmind.net/blog/2015/11/16/book-notice-kurzdorfers-reaching-the-top.html
http://www.jeremysilman.com/shop/pc/Reaching-the-Top-77p3905.htm
"Yes, you can easily become a master. All you need to do is some serious, focused work on your play.
That 'chess is 99% tactics and blah-blah' thing is crap. Chess is several things (opening, endgame, middlegame strategy, positional play, tactics, psychology, time management...) which should be treated properly as a whole. getting just one element of lay and working exclusively on it is of very doubtful value, and at worst it may well turn out being a waste of time." - IM pfren (August 21, 2017)
"Every now and then someone advances the idea that one may gain success in chess by using shortcuts. 'Chess is 99% tactics' - proclaims one expert, suggesting that strategic understanding is overrated; 'Improvement in chess is all about opening knowledge' - declares another. A third self-appointed authority asserts that a thorough knowledge of endings is the key to becoming a master; while his expert-friend is puzzled by the mere thought that a player can achieve anything at all without championing pawn structures.
To me, such statements seem futile. You can't hope to gain mastery of any subject by specializing in only parts of it. ..." - FM Amatzia Avni (2008)
https://www.chess.com/article/view/can-anyone-be-an-im-or-gm
http://www.cbsnews.com/news/kids-fight-stereotypes-using-chess-in-rural-mississippi/
http://brooklyncastle.com/
https://www.chess.com/article/view/don-t-worry-about-your-rating
https://www.chess.com/article/view/am-i-too-old-for-chess
https://www.chess.com/article/view/how-can-older-players-improve
Train Like a Grandmaster by Kotov
Becoming a Grandmaster by Keene
What It Takes to Become a Grandmaster by GM Andrew Soltis
"BENJAMIN FINEGOLD (born Sep-06-1969 ...) ... Ben became a USCF Life Master at 15, USCF Senior Master at 16, an International Master in 1989, and achieved his final GM norm at the SPICE Cup B Section in September, 2009. ..."
http://www.chessgames.com/player/benjamin_finegold.html
"MARK IZRAILOVICH DVORETSKY (... died Sep-26-2016 ...) ... He was ... awarded the IM title in 1975. Dvoretsky was also a FIDE Senior Trainer and noted author. ... During the 1970s, Mark was widely regarded by the strongest IM in the world, ..."
http://www.chessgames.com/player/mark_izrailovich_dvoretsky.html
"To become a grandmaster is very difficult and can take quite a long time! ... you need to ... solve many exercises, analyse your games, study classic games, modern games, have an opening repertoire and so on. Basically, it is hard work ... It takes a lot more than just reading books to become a grandmaster I am afraid." - GM Artur Yusupov (2013)
http://www.qualitychess.co.uk/ebooks/QandAwithArturYusupovQualityChessAugust2013.pdf
https://www.chess.com/blog/smurfo/book-review-insanity-passion-and-addiction
http://www.nytimes.com/1988/09/26/books/books-of-the-times-when-the-child-chess-genius-becomes-the-pawn.html
https://www.forbes.com/sites/alexknapp/2017/05/05/making-a-living-in-chess-is-tough-but-the-internet-is-making-it-easier/#4284e4814850

https://www.chess.com/news/view/is-there-good-money-in-chess-1838
"... Many aspiring young chess players dream of one day becoming a grandmaster and a professional. ... But ... a profession must bring in at least a certain regular income even if one is not too demanding. ... The usual prize money in Open tournaments is meagre. ... The higher the prizes, the greater the competition. ... With a possibly not very high and irregular income for several decades the amount of money one can save for old age remains really modest. ... Anyone who wants to reach his maximum must concentrate totally on chess. That involves important compromises with or giving up on his education. ... it is a question of personal life planning and when deciding it is necessary to be fully conscious of the various possibilities, limitations and risks. ... a future professional must really love chess and ... be prepared to work very hard for it. ... It is all too frequent that a wrong evaluation is made of what a talented player can achieve. ... Most players have the potential for a certain level; once they have reached it they can only make further progress with a great effort. ... anyone who is unlikely to attain a high playing strength should on no account turn professional. ... Anyone who does not meet these top criteria can only try to earn his living with public appearances, chess publishing or activity as a trainer. But there is a lack of offers and these are not particularly well paid. For jobs which involve appearing in public, moreover, certain non-chess qualities are required. ... a relevant 'stage presence' and required sociability. ... All these jobs and existences, moreover, have hanging above them the sword of Damocles of general economic conditions. ... around [age] 40 chess players ... find that their performances are noticeably tailing off. ..." - from a 12 page chapter on becoming a chess professional in the book, Luther's Chess Reformation by GM Thomas Luther (2016)
http://www.qualitychess.co.uk/ebooks/LuthersChessReformation-excerpt.pdf

Ben Finegold didn't become a Grandmaster until he was 40 years old

At 15, was BF a "USCF Life Master" or "barely strong enough to beat someone who just knows the rules"?

It's possible to be a GM... but not that soon or by 25. Maybe 40 or more depending on your effort and talent.

As some of the people on this thread have already mentioned, starting playing in USCF-rated tourneys at the age of 15 is too late to become GM by the age of 25.  But there is still hope for making national master before the age of 30.  Based on a  sample of master-level players across the country (currently still in the process of compiling) I compiled in my spare time, out of those who played in their first tourney somewhere in-between the age of 15 and 25 [n=11], ~64% of them went on to crack 2200 USCF and obtain the national master title by the age of 30.

Once I am finished compiling the sample, I can give you a better estimate.

Don't give up! I guess you can be GM but like WilliamJohnB said you can still try for national master. All the best!

It´s not too late but it´s probably impossible. Very few can do it however hard they work. But maybe you can.

As "kindaspongey" points out, Ben Finegold, the son of a chess master, became a life master at 15 and an IM at 20. For years before he finally nailed down his last GM norm, he sometimes called "the world's strongest IM.:

Very unlikely. Enjoy the game and spend your energy on getting a good education...

Well, you would need to play more than just every now and then. So it adds up to how passionate are you actually on this matter? Your passion, interest and inner drive will be your engine so to speak.

A part from that I will say that kindaspongey's long post, post number 4, gives you a lot of ideas to chew on.

When you say "give your life to this game," that's what it will take just to have a remote chance of becoming a GM beginning from a lower-rated player at 15.  We're talking about 6 hours/day of lessons, training, playing. memorizing - instead of developing skills in something like engineering, IT, science, medicine, accounting, business administration, teaching, plumbing, carpentry, etc..

If you do achieve GM and then retire, think of the skills you will have given up to do so.  If you do reach GM and decide to stay as active as possible in chess: playing, lecturing, teaching, writing the next book called "A Relentless (or Strategic, or Attacking, or Devastating, or World Champion or etc.) Repertoire for White (or Black), you will most likely find yourself struggling to make ends meet.

I coached a very successful high school chess team and teens new to OTB chess who became so enthused they said they make chess their life usually did NOT remain as players long - they got too into it and burned themselves out.

We also had a chess.com member about a year ago, a teen from England, who often proclaimed on thisforum, "Chess is my life!" who is no longer to be found here.  We had another in the past year who may be still around but hasn't posted anything I've read lately who proclaimed that a 1200 rating made him a "chessmaster" and frequently posted idiotic things he claimed only he could see about chess.

As others have said, enjoy the game and work on developing skills to make your life's journey a pleasure.

You're not going to become a GM. Maybe it's possible. Even if it's possible, it's not going to happen for various reasons. I'm not going to become a GM either. 

And you shouldn't think about that. What you should think about if you want to improve at chess is what you can do to become better at chess today. Or what you can do to achieve a certain rating by the end of this year, or to finish a certain book you're studying by the end of the month, or to achieve a desired level of understanding of a type of endgame, or an opening, or to achieve a level of tactics rating on a site like this.

You're vastly better off setting more short-term goals which you know are possible than one far-off long-term goal of questionable possibility. 

Don't listen to the naysayers. An hour a day for about 6 months is all it will take, and you will likely be a GM before your 16th birthday. Pick up the piano as well....with just another 20 minutes per day studying piano, and you should be a world class musician in about a year. That would give you a solid "plan B". 

Until you are an IM looking towards GM is pointless.

Sounds like the sort of excuse I'd whip up a few years ago for my own lack of improvement

Do i a 13 year old have any hope??? I learned chess when i was young, then did not play moch but, this year janruary i dug in..

Yes. Still play for enjoyment, though.