Okay, Like everyone else is saying here, go for it. I do have one additional bit of advice. As some have said ask about wig, bra, and all other things like make-up. Just when you ask these things act as unknowing as you can...don't act like you know what bra size you wear, or anything. You know nothing...At least that is what you have to have her believe, if you want to stay as an undressing man to her. Oh and when you tell her that you would be willing to try, ask her why she ever thought about prom dresses for you as a costume......