Wait...does this also mean that different classes advance at different rates?The important thing to remember is that ENWorld plays by AD&D rules, and consists mostly of narrow corridors full of humanoids with weak saving throws. If you rely on charm person, you'll do fine. If you start slinging fireballs, you'll just blow yourself up.
Thief it is!
I think you need to get recommendation for posts you make. The number of these posts is revealed up to level 5 (on some page on this website, I forget where), at which point it's hidden.