I think the preflop action was fine, although you definitely could get more in if you wanted to take down the pot there or isolate against another big pair or AKs-AJs.

IMHO, and as noted by other players, you make a big mistake on your flop play. I think in this situation you have one of two options:

1. make a large bet (i.e, psb) and see where you are at. If the guy makes a shove into your bet, then you have some thinking to do, otherwise, you call or re-raise anything reasonable, or

2. check to induce the bet (which is what happened here). Many players when checked to will bet out hoping to take it down with a marginal hand. With AA, that just might be the right line on this board. Since it was the one taken, your mistake is not making a substantial raise to put the villian to the test.

While a good deal of poker is about ranges and the cards you get, a large part of it is making the other guy make the tough decisions. A raise on the flop after the check, or a substantial lead out, does exactly that.