Playing baritone or any other instrument doesn't have to mean the total loss of your trumpet-playing ability. Back in my school days, we had a lot of trumpet players, but occasionally found ourselves temporarily short in other sections. With three of us about equally capable of covering first chair, it was no big deal for one or even two of us to move to baritone or Sousaphone for a while, then move back to trumpet. I did it quite a bit, and enjoyed the time in the low brass. For a while, I even played Sousaphone exclusively in one band while playing trumpet in my regular school band. Enjoy it.