As a current cheerleader and dancer, the best sport I do while in on off season, is track, or I choose to simply work out. Dancing has a lot to do with building your calves and leg muscle, which I'm sure you're very used to as of now, track keeps you in the same shape as dancing will, or cheerleading is another suggestion but it requires many tricks, and hard work in order to be "the best" amongst your teammates on one team! Always work out if you choose not to do any sport because it keeps you in shape and very healthy!
What do you think would've happened if all the people who won So You Think You Can Dance gave up at age 14? There wouldn't even BE a So You Think You Can Dance! Please reconsider this, you won't regret it.
Keep dancing. If you're aging out of competition, I'd say give ballet a try. You already have the flexibility and strength built up, just now you need technique! And you're never too old to dance- my mom is 35 and still en pointe :) she's a crazy Russian ballerina, so she's much tougher than most and still thinks that she's 20!