Go and don't sweat it. EVERYONE there has BTDT where you are now. Best advice I can give is grab one of the upper class fliers to help you. Have the CD announce you're new to the sport and I bet at least a dozen hands will go up as willing to help. First flight will be the hardest. Don't sweat it dude. Even FAI fliers flat blow a flight once in a while.
Do each maneuver as a single deal. Don't worry about the next one at this point. If you find yourself getting too close in or to far out turn the airplane in or out and get back on line, this is preferable to possibly crashing the airplane trying to do something right on top of you or out so far you lose orientation awareness. I'd rather see a new guy get the airplane back on track from an extremely too far out or in line than take a chance on crashing because you can't tell what the airplane is doing, even if that means turning the airplane 90 degrees and flying back to the proper line. No flight is worth crashing over. Forget trying to stay exactly online, be close. I bet if you watch most of the flights by other fliers they won’t be exactly on line during their flights either. Many of them have been doing this for over 20 years! Believe me it's much better to get a zero than pick up pieces. Oh and you won't be the only one getting a zero during the weekend, there will be plenty of those going around.
I've coached many a new flier at a contest and it helps to have your caller help you fly the airplane. No one cares if you blow a flight or single maneuver, they do care if you kill an airplane. They want to see you at the next contest and the next.
If you have someone at your home field then by all means have them call a few "rounds" for you to get used to having that done for you. Don't try to be perfect because you won't be, no one is. The big deal on the first contest is to learn how a contest runs and how you fit into it. By all means have fun, it’s not uncommon to hear someone laughing their butt off while flying about a blown maneuver.
Remember, cutting a fabulous diamond always starts with knocking off the rough edges first then they start the polish to get a high shine. Pattern flying is no different. Have fun.
PS What ever you do DO NOT ask ANYONE about Spin or Snap entries. You'll be there for days.