Were you ever in marching band? It can be a great time if you like music, and it is a great way to make friends
Yes. I played trumpet. We had a great band teacher. Marching bands have a lot of brass, woodwind and percussion instruments in them most of the time it seems. 
I was never part of marching band but knew a lot of kids who were, I always thought the drums were very cool
Most of them wear military style uniforms with the schools name or symbols, and they are hot if you're outside. 
That does not sound fun, I do not remember uniforms, that would be enough to turn me off form it
It wasn't. On top of traditional parade performances, we had to learn field show at sporting events.
I do remember seeing some of those for our pep rallies and all that, which was always cool. I wish I would have started in middle school
. (https://marching.musicforall.org/directorinfo/)
A: up to 600 students
AA: 601-1250 students
AAA: 1251-1750 students
AAAA: 1751-2250 students
AAAAA: 2250 + students
History.
Percussion and wind instruments were used on the battlefield since ancient times.
An Iron Age example would be the carnyx.
The development of the military band from such predecessors was a gradual development of the medieval and early modern period. 
A prototype of the Ottoman military band may be mentioned in the
pep band is the same as most marching bands, using mainly woodwind, brass, and percussion instruments. Pep bands typically don't use primarily orchestral instruments (double reeds, strings, etc.), but this is not a hard set limitation.
Pep bands have been in existence for a very long time, however their origins are vague and hard to find. The concept of pep band most likely sprung from marching band (a band during sporting events with choreography while they play music, normally with uniforms).