I am 16 also and weigh, as far as I know when I weighed myself this morning 169 pounds. I am 5 foot 7 inches also and I am in the same problem, though I only take dance lessons once a week, but I have been practicing till yesterday since my foot is messed up. And I sometimes work out, lately, not as much lately (My passion is in guitar and drawing/art lol, and my cousin is over so it's PARTY LAZY TIME! :D) And my legs are naturally muscular, always have been so I don't know if there is anything some of us can do about that whole muscular look on our legs. If you are really exercising that much, then you shouldn't worry too much, and a lot of girls have stretch marks :) there is a cream that can help you with that. And as long as you don't skip a meal, and it's healthy, that's good and you should be losing weight. But calories do play a roll in this, I have been counting my calories for a little over a month now, and I have lost at least lost 7/8 pounds. I went vegan back in October last year (where you eat nothing but plant based products, no dairy or meat, I am sometimes vegetarian here and there though, where you eat dairy products but don't eat meat.) and I used to weigh almost 200 pounds and within a couple of months I instantly dropped 20 pounds! If you are 5 foot 7 inches though, you shouldn't weigh more than 150 though. So if you are 150, you are good the way you are, and you don't need to lose anymore really. (I am going by BMI also by the way).
But I hope you reach your goal and don't put your health in danger!