Aaron, congrats, and Rel's advice seems to apply here:
1) Have fun, and
2) Don't care (or the ladies corollary: "don't become emotionally invested on the first date.")
1) If what you are out doing on the date is fun for you (and her of course), it'll show unconsciously in your actions and mannerisms. Whether the date pans out or not, you're still having fun.
2) Not caring means try to ease up on "what the future holds" and "what the date means", etc. and enjoy the time out for what it is - time out with a close friend. If it develops into more, then great, and if not, then you don't get stressed about it. And it usually subconscious ALSO shows up in your mannerisms and such for the date.
I Hope you have a good time and enjoy yourself!