[PeteB570]

Maybe, maybe not.

Some abilities can be sharpened if they are there to begin with. If there is no ability then there will be little gain.

Since I didn't apply myself in that direction I'll never know one way or the other.

I would think that putting work and effort into getting into college would have better results than trying to play world class chess. After all, most college students have a public school background. :-)

[GSlob]

"Maybe, maybe not"
Probably not. There was a guy - Mikhail Botvinnik, former world chess champion [and a professor of electical engineering at an elite engineering school in civilian life]. He used to run a "postgraduate" chess school for prodigies - those who did start playing around age 3 and got to international master level by early teens. Many tried to start early, not many got to that level. Kasparov is his best pupil, so you could imagine the kind of selection he went through.