I didn't know what I was until I found out about asexuality when I was about 20, but I didn't have a bad childhood in that regard, I was fairly oblivious to peer pressure and thought I was the only one with any kind of willpower or common sense surrounded by shallow insane sex maniacs. We live and learn!

In any case, I don't think we ever know ourselves 100%, even if we live for a hundred years, it is a constant journey of self-exploration and analysis. Orientation is obviously a biggie, but at least some things we can find ourselves content enough to say "you know what, I don't care what I am, I'm me"