You'll be fine. Just try to keep it light and have fun! My first time, I thought I was going to die. A buddy of mine's Dad was the Union boss for a major auto MFG, and for the company picnic, he wanted our band to play. None of us had ever been in front of an audience before, and I was the front man and lead singer as well as rhythm guitar! Yeah.... well.... little did I know just how many people would be there.... try 4000 on for size! A literal sea of people, and we are the main act, and I'm the flippin' star??? What??? I wore a white shirt that day, cause it was summertime and figured it would keep me cool. After the show someone came up to me and said "Man, you guys were great! There was only one thing, your face was as white as your shirt!" LOL!!! 

Well no chit! I thought I was gonna pass out at any minute! Did the gig for free too... to get experience. Man did I get it!
The good news is that it instantly cured me of stage fright, and I've never had it again
So... if I can make it through performing in front of 4000 people as my first time, I'm sure you'll have no problems! Good luck man!!!