I read most of both of TAOCP and CLRS when I was in my late teens and early twenties. I couldn't follow the most difficult mathematical bits, but I don't think it's THAT unusual to have worked through most of both of them.
In high school read/studied Ivan Hortan's beginning C++ one summer which what an awesome foundation for collage programming courses. Now, I thought it as well worth it and recommended that book to several people. But here is the thing it took most of a summer, and I stopped around page 700 or so. Further I am not recommending someone read it, I am suggesting they spend a few months studding C++.
TAOCP is not a book it's 1/3 of a masters degree in paper form. Suggesting someone read it is like sugesting they get a MS useful, bit not quite the same as recommending a normal book.
