In sports, you can usually play for the school, but if you want to play outside of school, you may have troubles finding a league to play for. There are probably a couple leagues in Florida, but how close to the city you're in will vary. I mean if you really wanted to play, you could drive the extra distance to go there or you may have to convince your parents to take you if you can't drive.
For example, volleyball is getting more popular, but isn't really that popular yet, so if there is a different sports league near you, just try it for fun. When you get a little older and want to keep up sports, you can get on adult leagues. If you're looking for adult volleyball leagues in Florida, you can check out your local YMCA or park for more information if they have a league.
However, if you can't find adult volleyball leagues in Florida, and you don't want to try another sport or drive; you need to keep your skills up for the following school year. You could do some volleyball drills if you had the place for it and if you were a setter, you may want to try going to some volleyball setter camps on the off season.