A good thing to think about with these social situations that I always try to do, because I used to have pretty annoying social anxiety too is:
how much attention do you pay to the people you see passing by?
I used to get nervous just in a store wondering what the person in the line behind me might think about my groceries. But then I started thinking if I could remember how the person infront of me in the line even looked and what they were buying.. I had no clue.
So, there's that approach. And then there's another approach: What if there's a person paying really close attention to you? There's 2 things this person could be thinking, something nice and supportive and something mean and intolerant. Too bad you can't hear the supportive persons' thoughts. It be like you have us 3FC chicks with you everywhere

. But that means you also can't hear the intolerant thoughts. If you could, would you care? Does it REALLY matter what an intolerant person thinks about you? If somebody has enough time to waste on thinking bad stuff about others I pity them. They appearantly don't have enough positive in themselves to be doing what they are doing and enjoying themselves without paying attion to some one else.
Either way, you HAVE TO GO. You said you want to. So don't let this worry stop you. And once oyu get there, breathe in and breathe out. That's basically all you have to do. And instead of being impressed by all the people that look like they know what they are doing be happy that you have so many examples of how to do something. Don't be afraid to look and ask.
Have fun!