Hey Alex!
When I think back to when I was your age, I really wished I had gotten more involved in math competitions. Does your school have any programs like MATHCOUNTS, AMC8, etc.? I didn't compete in any academic competitions until high school, and I really wished that I had known about them earlier on. It makes getting ahead in math so much fun and it helps lay some really important foundations for the more complicated stuff.
Anyway, keep up the good work!
Also anything by Martin Gardner, because his books are so much fun and help to spark your imagination.
At a young age one of the most important thing to develop is a habit of perseverance and not giving up when trying to solve a problem and avoiding developing areas of learned blankness. You should develop an unfaltering confidence to use your own head when trying to solve the problems. Sharpening mental capabilities and developing good mental habits and attitudes seems to be more important than learning more things (for example, the author of many AoPS boo...
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A list of some posts that are pretty awesome
I recommend the major sequences to everybody, but I realize how daunting they look at first. So for purposes of immediate gratification, the following posts are particularly interesting/illuminating/provocative and don't require any previous reading:
More suggestions are welcome! Or just check out the top-rated posts from the history of Less Wrong. Most posts at +50 or more are well worth your time.
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