Historically, most GM's were already masters by their early teens so if learning the game at age 8 or 9 is no longer and option for you, your lofty goal has the probability of attainment equal to the life expectancy of a snowball in hades. Sorry.
Serious Question
When I win tournaments, you won't know anyways, so why would you bother spreading negativity? I am a Human not a machine.

Why is everyone obsessed with being a GM, only a small , small percentage will ever obtain that, play for fun and growth.
Because GM's have class and style.

Since you didnt say what your OTB rating is (if you have one) I can only go by your chess.com ratings. Why are you worrying about competing against GM's? when you should be worrying about competing against players +200 points above your rating. Lets say you are a USCF Class D player. Play up against C players, and progress from there.
I admire the determination, but you have to learn how to crawl before you can run, let alone walk.

I believe blitz is a waste of time and doesn't help anyway in serious chess improvement and understanding. I think Botvinnik would agree with me.
This is one of the best things I've read today, thank you for the laugh. Yes, I think Botvinnik would tell you to quit playing this silly blitz chess and instead brush up on your endgame technique... joy.
He will also probably let you know that you don't have a clue about chess, and that you have no future at all in this profession.
Well, Botvinnik has been wrong before:
The boy doesn't have a clue about chess, and there's no future at all for him in this profession. - (on student Anatoly Karpov)
But probably a good guess on his feelings about blitz:
Yes, I have played a blitz game once. It was on a train, in 1929.

I believe blitz is a waste of time and doesn't help anyway in serious chess improvement and understanding. I think Botvinnik would agree with me.
I would have to disagree.
I recently added blitz 5/0 to my prefered time controls; 30/0 and 3 day/move games.
Used as a tool, I am finding blitz is great for imporvements in some areas of my game:
- Opening exploration. I can practice against a lot of random responses to my openings. This really helps me get to know an opening and understand the moves much better.
- Experiment with strategic ideas. I am finding, at least at my current level of blitz play, that there are very often opportunities to implement stratagies that would be difficult to implement in slower games. By trying these ideas in blitz, like the openings, I get to know them and understand them.
- 'automaticize' checking for hanging pieces, blunders, simple tactics and other important basics. I have really started to learn how to organize my process when looking at a position. Even in slow games, you look for the same exact things in the position as you do in a blitz game. So by being forced to do it quickly AND accurately, in slower time controls, that is just a bit more time I have to devote to planning and calculating.
So here are some things I've gotten out of playing blitz. However, as I mentioned above, this is using blitz as a tool, not just a form of chess playing pleasure like slower time controls.

I think it is mostly about comfot levels and goals.
When I first came to this site, I played 15/0 and 15/10 games. I thought that was a good time. Until I started playing 3 day/move games. Then I began to realize they were 2 very different games.
I would say only go as low as you feel there is still a benefit of some type.
Historically, most GM's were already masters by their early teens so if learning the game at age 8 or 9 is no longer and option for you, your lofty goal has the probability of attainment equal to the life expectancy of a snowball in hades. Sorry.