2nd hand in a live $50 MTT

Im on the button 2nd hand with AA and a $2000 stack. The blinds are 10/20 and there are 4 limpers to me. I raise to T100 (I think this was my main mistake here, should have raised to 250) and there are 4 callers

Flop Q [img]/images/graemlins/diamond.gif[/img]7 [img]/images/graemlins/spade.gif[/img]8 [img]/images/graemlins/spade.gif[/img]
Check to me, I bet 400 into a pot of 500 and get 1 caller (who is unknown)

Turn T [img]/images/graemlins/heart.gif[/img]
Villian checks saying "Your turn son" and smiling (Note Im 22 and look like a kid and hes like 123123 years old)
I think for a while, and decide that he must have 9T of spades, thats the only hand he could confidently call on the flop. (Im excluding sets here since I dont think he would have talked at me with a set on the turn)
So I push my remaining T1500 into a pot of T1300 or so

How did I play this hand wrong and what could I have done to get away from it. What do you guys put him on and can you check behind on the turn here?