You're probably already playing by now, but maybe the Good Luck wish will extend till next time. Nerves are a killer the first few times you perform for an audience, no matter what size that may be (other than what I had to endure being thrown to the Lions for my very first gig. I don't recommend it for health reasons,ie; GUT-ROT). First time out was opening at a Street Festival with over 2,000 Headbangers attending. It took everything I had not to blow chunks all over the crazed metallers moshing right up to the stage!!!!!!!!!!! The only two things I can remember besides my rotting gut pushing that Burger King Whopper into my throat (ate something to calm the nerves, Bad Idea), was how difficult it was to control tempo and fighting the strong urge to speed up. And secondly, making a mental note to bolt down the Monitors next time.
A band named Vengence (now go by Vengence Rising) headlined that gig, until the were forced to shut down for fear of a riot brewing. Needless to say, the promoter's never booked that line up again.

One thing worth noting was the stage used by Vengence. It was a 40 foot long Flatbed Tractor Trailer. That band totally ripped, I've never seen a band perform on a flatbed before and it made for an awesome looking hardcore stage. Wish I would have thought of it first.
Good luck. After a few bouts, your nerves will calm some, however, I still get butterflies to this day before the gig, but that initial urge to speed up has faded out, thank God!!!!!!!!!!!!!