Like the other said, you can always do a combined test or choose one discipline that you particularly enjoy, such as just dressage shows, or focus on jumper or hunter. Cross Country isn't for everybody and it takes a lot of work, especially since it's leaving the comfort and safety of the ring.
Hunter paces are a great way to get used to it, though. Some Hunter paces will have two different divisions: Hunter, for those who compete at a faster time to simulate a foxhunt, and hilltopper, which is slower. In the ones I've done, all jumps are optional, meaning that if you don't want to jump some, you can just go right around. They're timed, though, but it's not about speed. Rather, it's about being closest to an optimum time. You also usually go in teams of two or three, which means that it can be a lot of fun and easier for horses who get anxious when out alone. For those who aren't comfortable with cross country, hunter paces can be a great way to get out there and just have some fun while you practice.