Who do I slim down muscular legs and get rid of arm fat?

Ok. I'm 15 yrs old, 4"10, 47kg and I do taekwondo and I have very big legs, both calves and thighs. The fact that I'm short contributes to how bad they look. My calves are mostly muscle and my thighs have fat and muscle, so it looks big. I do stretch. My friend is in track and field and her calves bulk up, and they look bad. I want to give it that nice slim shape. I know it's possible. I see videos and stuff, but the trainers have bulky legs too. Am I looking at the wrong videos? can you suggest me any? what should I do? I also have a hand full of fat on my upper arms. I do push up so if i get rid of that fat, my arms might look nice. Suggest any reads and stuff? I just really need help.