stage manager vs. performer...?

so today i got offered the chance to become the stage manager for my school musical. this is a HUGE honor, hardly anyone gets asked. But its also a HUGE comitement which i dont really have a problem with. I get alot of authority and it'll be alot of fun, but at the same time i'd give up being IN the musical (as a lead) im a good singer and i actually had a chance of being a lead or princaple character....also if i accept the stage manager, id have to do all of the rest of highschool....so i cant do stage manager one year and be a performer the other....which should i pick?!?!?!? thankyou for helping in advance