You would be in EM (E Mod) class. That's a rough class with purpose built racing cars with turbos, superchargers, engine swaps and racing slicks (not DOT R tires).

Your first year is a learning experience anyway, so the only thing you should be worried about is being consistent to other people in your class or other classes. Find someone who is a veteran and try to stay consistently behind him. Each autocross is seat time and you want ALOT of it. I attend about 40 autocrosses a year and also do novice autocross schools. The more autocrosses and seat time you get the better. Also ask if you can have an instructor ride with you, you have the instructor drive for you, maybe jump in other people's cars, and of course there are fun runs. Usually at the end of the event.