Road to becoming a U.S. National Master.



No.
Yes.
As is typical of any new person in any field, they ask poor questions.
This is a poor question because there's no magic bullet. There's no number of books, or number of games, or number of hours, etc. You get a master title by scoring roughly 50% against masters. So play and learn.
5 years, you're already an adult, I assume with some mixture of a job / school / relationship commitments...
Realistic is like, 1200 -- because you wont waste much time on chess, and instead you'll have a job and family.
If you're passionate about chess and don't have a competitive job or a meaningful relationship then maybe 1600.
If you're passionate and sacrifice other things, then maybe 2200.

I'm not a master, but my online rating here is 2200 which confuses some people into thinking I am
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The point is that I didn't begin chess to "be a master" and I don't think real masters did either.
People who love chess play a lot, and love to learn and improve. They do it passionately even if they're not promised fame and fortune.
So when a new player asks what they can expect after 5 or 10 years of hard work... it's not a good sign My first goal was to be 1300. My plan was to quit after 1300. My motivation was that no matter how much I improved, there would always be someone better to test my limits against, and no matter how old I got, I could go to a tournament. I wasn't interested in fame or fortune (I went to my first tournament at age 21 by the way, so I came into chess late too).
If you chase a rating, you'll definitely improve, and have fun... but comparatively you wont get very far... that's my two cents (again). Alternatively, if you chase knowledge and if you genuinely enjoy chess, then you'll go far. 20 years old is not too old. I didn't get a title, but it's not like I did everything I could (or even close). You could... but focus on learning, not on a rating

I stopped playing USCF in 1973 after I had met the requirements to become a NM. [liked correspondence chess much more] [because of a health problem]
Back in the day I played in many USCF chess tournaments [and did well]--that is one little secret] The other secret was to find out and fix your mistakes. At you current rating [1200?] you are making as lot of mistakes every game. You shjould emphasize is to find your mistakes--you will need help with this probably. write down your mistakes and try very hard not to repeat your mistakes. Also, of course, use all the available learning tools--there are a heck of a lot of them. I would guess in about 5 years you might become a NM.