Good advice for any sort of public speaking event, treat the actual event as if it were practice. Now don't get me wrong, that doesn't mean you shouldn't practice before, but also don't go in with the attitude that it's your big shot. It's not. Just treat it as another chance to get some experience under your belt. If you fuck it up that's good. When you've never failed before, failure is much more terrifying. After you've screwed up a few times though, and seen that you could still get back up and try again, the fear won't be near as bad. So treat it like that, and remember that there will always be another opportunity to try again. As long as you don't let anything that happens get to you, you'll be just fine.
As for the actual material, just do the material that you want to do. With exceptions to a couple things (like keeping material appropriate for your audience so as not to offend) you shouldn't try to tailor your material to your audience. If you try to pretend that you're someone you're not, it'll be clear as day. An audience can smell a phony a mile away, being a good liar is way way harder than being honest. Our species is very attracted to those rare few who can be honest about themselves, we like people who are confident in who they are. So go up, and tell the stories or jokes you want to tell.
Most important of all though, just have fun with it. The more fun you're having with it, the more fun they'll have with it.
