During my first op I was so in awe of the whole thing that I omitted to ask anything.
The second time around I made sure that I asked the surgeon to explain how he was going to fashion the new clitoris and hood - whether I would have any labia minora, how he could ensure that my urethra ended up in a normal position. What could be done to ensure that things remained sensate (as a major risk with second ops is that you can lose sensation) etc etc.
As it's your first op I would suggest also asking about depth, about the advisability of prior pubic hair removal from the tissue that is going to be used, and indeed anything else which concerns you.