you can start anywhere you like. you can start in pro if you wanna pay the money.
what kind of equipment are you using? what kind of yardages are you used to shooting? how long have you been shooting?
I am shooting a mathews outback with a 5 pin dead nuts sight and a QAD rest. I am good out to 40 yards and I have been shooting for about 5 years for hunting.
you should start in novice or bowhunter. either class would work well. novice especially if you have not shot tournaments, but if you have go bowhunter class for more of a challenge.