What are my chances at MiT, CalTech, Harvard,...

This should be an essay topic, or at least a substantial portion of one of your essays: Taught myself operational calculus (I’ve taken derivatives and integrals with algebra to derive physics formulas, though I didn’t know that’s what I was doing at the time)

From what I see, you have several good hooks and activities:

  • URM
  • Chess. There is a big difference between what most people do (start a chess club, that’s it) and what you do (play competitively and succeed, as demonstrated by your ranking).
  • Four languages, parent-teacher translator
  • Comic book club (This sounds interesting to me; you might want to incorporate it into an essay depending on your involvement with the club)
    I like the spread of your ECs – Clear focus on math and sciences, yet some developed interest into the humanities. Your volunteering (aside from park ranger assistant) corresponds well to your main activities and interests. This is something you should be able to play to your advantage.

I feel as though other commentators looked merely at your SAT score and then decided that you have no chance. My suggestions would be, as far as standardized testing goes:

  • Improve SAT Math to 700 - 800
  • Take SAT Subjects Math Level II (800 here would be nice) and Chemistry / Biology / Physics

Finally, to confirm what has already been said: https://www.bostonglobe.com/metro/2015/03/16/suicide-rate-mit-higher-than-national-average/1aGWr7lRjiEyhoD1WIT78I/story.html