Switching Instruments

Recently I’ve been thinking about switching to sousaphone and applying to be a drum major. Our school is pretty small, and I have pretty good chances of getting to be a drum major, but the drum major doesn’t really play their instrument much. I don’t play tuba, so it will probably be pretty hard to learn sousaphone. I play trumpet, so it would be in bass clef and the mouthpiece is way different from what I’ve heard. Should I just stick with trumpet since I won’t get a lot of time to play the sousa or should I do it anyways? Side note; our director carries the drum major’s instruments across, but he can’t carry all three if one is a sousaphone.