I feel for you, kiddo. I may be in a relationship, but I've never been on a date. (Not even kidding.) Granted, I'm sure that when I'm hanging out with Freya and keeping things somewhat PG would be about the same as a date.
There's a good chance that she.. (he?)... is going to be just about as nervous as you are. So just do your best to relax and try not to make it too much about you. Ask her questions and answer hers.