Either wear something nice for her, or if you want to be audacious, try something you can at least pass off as not out of "Dumb and Dumber" because all it will do is make you out as a jerk. You could try, if you want to be risky a Kilt bottom (tartan) and a tuxedo top. It would be different, and would stand out, but would be classy rather then emberrassing. (and what is it with these foolish youth! For pete sake, between this kind of thing and Antonio.. damn boys, where's your lady handling skills!) I think even though she may say that, if you go through with it, you're going to hurt some feelings.