I ride on my schools equestrian team, but full disclaimer, it is not an overly competitive team. I would try to get out to as many schooling shows, clinics, and shows as you can, and ride as many different horses as you can. I'm in canada, and the way we show, we arrive at the facility and draw names out of a hat to see which horse we will be riding. So you're riding a horse you've never sat on before every time you go to a show. Becoming a diverse rider is one of the best things you can do especially if your goal is jumping.
Our show series is equitation, so depending on where you end up going to school, you may have more choice than that.
We had a placement day at the beginning of the school year where we had try-out rides. They placed us in lessons that were best-suited to our level. Don't worry if you feel like you're not good enough, or can't jump high enough (depending on your discipline). For our shows there was everything from 2'6 to beginner walk trot. No matter your level, you should be able to have a good experience on a team.