I think you should speak to your private voice teacher, if you have one, about this. Many high school aged singers can healthfully navigate the musical theatre world provided they are working with their private teacher on choosing age appropriate repertoire and still singing with healthy technique. Mics prevent the absolute need for belting. Choral singing needs to be done healthfully as well otherwise one does run the risk of vocal abuse. Best of luck to you in your high school singing experience. 