Should i have layed down my AA?

[n1stunnor]

Here's the scenario......

I was playing in the Truepoker freeroll and had made it to the final table.We were 4 handed and i was on the button with 55k and the limit at 4k/8k.The player UTG raised to 8k.I re-raised to 12k,the blinds folded and UTG called.Flop came KJT rainbow.UTG checked,i bet,she raised,i called.Turn came rag,she bet,i called.River came rag, she bet,i called.She turned over AQ for the straight.This crippled me seriously and 2 hands later i was out.

Let's get some opinion's on what i should have done.Thanks