I'm sure you realize that you can't just show up and expect to be welcomed in to any theme camp you please, except if you're a buxom blond, brunette, or redheaded chick with a half-way decent physique...otherwise, start the process of scrolling thru the listed camps, narrowing it down to a few that sound like a fit.
Contact the camp's point of contact and sell yourself...what you bring to the table. All of the camps have space/peep limitations. Some have already max'd out their rosters, some are still looking for camp mates. Some charge hefty camp dues, some nothing. Some have huge time/work commitments, some nothing at all...and there's everything in between.
Suggestion: This is your first year. Since you need to arrive fully equipped with all your food, water, and shelter anyway, just set up your camp on your own. Wander around enjoying the sights and sounds. Drop in to a few of the theme camps and get a first hand sense of who they are and what they're about.
Theme camps are not the end all/be all. When you get to BRC, you'll more than likely end up in the best possible place, meet the greatest people, and have the best experience of your life...just let it happen...
But don't come unprepared...the playa is a harsh mistress...read the Survival Guide many times and heed it's tips and warnings.
Don't bore your friends with all your troubles. Tell your enemies instead, for they will delight in hearing about them.