New_romantic_smuggling

Hey guys, I'm currently 17, a senior in high school, living in Arizona, and I'm interested in auditioning for a core. However I don't know if I should start with open or world class, because The Academy is actually not too far away from where I live, and I was thinking of auditioning there to begin with because they're so close! I want to audition for a marimba part in the front ensemble because that's what I mainly play, however I was thinking of auditioning on synth or possibly for colorguard too, because I have some experience with piano, and I did winterguard for 2 years at my high school. But as far as class goes, what would you suggest?