Hey Joni1!
I have done some burlesque performances before- both of them were at least semi-choreographed, and both of them I was horribly nervous for! I don't like being on stage, in front of people, and... well, I guess I decided I was crazy because I did do it!
My first performance I did actually screw up. I had the timing of the music down, but not my own timing- both my gloves were off in the span of time it should have taken for one of them! I realized this about partway through. I knew my music well enough though, and improvised the corset removal to be longer. I teased the heck out of that audience! It was a lot of fun, and I wouldn't have discovered it had I not been so nervous and screwed up a little bit.
On the flip side, I did my other performance fairly well, and got... lackluster response, mostly due to my music. I was also really nervous for that one, but I remembered everything I'd wanted to do.
So, couple tricks for you: Firstly, practice! I know you have been doing, and I know how very boring it can be. You just want to dance, why do you have to do this routine AGAIN? Ugh! But, it can save your bacon later- knowing your music, knowing what you wanted to do if you screw up (so that you know where you want to be, and can get there, and make it look kinda good!), and besides that, it can really help with the anxiety of performance. You can tell yourself "I KNOW this routine! I'm going to ROCK this thing!"
And that's my second trick: Tell yourself positive things. I can't tell you how important this is! Tell yourself you're going to rock, you're going to have fun- you're not nervous, you're excited! The things you tell yourself become a big part of how you feel. This is actually a huge part of Cognitive Behavioural Therapy, which they use to treat things like anxiety in daily life. Tell yourself good things, be nice to yourself, and suddenly... you won't feel so horrible about stuff.
The incessant "What if"s that you're running through can be really freaky, and I know that they plague me daily, constantly. It's an issue I'm dealing with. But, you can try to answer those questions and see what happens. What if you blank out? Listen to the music and take a moment. Do some sexy stuff- people like the sexy stuff. What if you're so nervous you throw up? Well, I have a friend who does that with things like public addresses, and she just tries to hold off till she's done, and then she runs off to the bathroom. See about doing that. Work on slow, controlled breathing, eat a proper meal, give yourself time to digest before performing. What if you fall on your head? I'm pretty sure all pole dancers have to face down that fear, even without performing! I'm sure that, by now, you're able to detect whether your hold isn't quite right, or your slipping a little bit. Breathe, and think of some ideas on how to counteract those issues.
Mainly, have fun. I know that everyone says that, but if you've ever had the mentality of "Laugh it off" then that's the best one to have when you're performing! Things will go wrong- I've seen girls slip on stage, lose their pasties, have zippers get stuck, all of that. It HAPPENS. It's just like any major event in life- weddings, babies, christmas parties.
I'm excited for you! You're doing something amazing that you've always wanted to do! Go get it, and be just as awesome as we all know you can be!