Fitting in ? :\ ! HELP!?

Go for it! It'll be a big group, so no one will notice if you're not participating as much as other people. But you should put in a little extra effort to talk to people and loosen up a little. See if you can ride with your friend or meet him there so you aren't by yourself when you first get there, and maybe he can introduce you to people. You can always leave early if you feel uncomfortable, but give it a chance.