Should I agree to be part of the wedding dance - I'm a transgendered (pre-op) girl?

[Sheila]

As I wrote in a question recently, a few months ago my college roommates convinced me to let them help me out w/trying to present myself as a girl - it's been awesome! Socially, I only present myself as a woman now - though I still go to school in boy clothes - yuk. I don't really look much like a guy anymore even when dressed like that though I don't quite look all girl either, without makeup and the right clothes.

One of my roommates wants me to be in her wedding as a bridesmaid. (See old question). I've agreed - but I'm still holding my breath - she seemed very happy w/my decision. So today we're talking about the wedding which I loved - she is one of my best friends. Among other things, she mentioned the bridal dance and kidded me that she'd need to see which of her fiance's groomsmen is tall - I'm 5'8" w/o heels. Now I'm in a panic - I'm really worried the guy is going to embarrass me! She's so nice but should I just refuse? Or ask to talk to her fiance? Help!