My brother and I are 4 years apart. I immigrated to the US at the age of 5. He arrived later 5 years later at the age of 14. When we reunited, there was a noticeable difference in our appearances. I was lighter, taller, meatier, and looked all around more healthier. He, on the other hand, was the opposite (having come from a 3rd world country). I was an inch or two taller than him. I felt like a South Korean soldier next to a North Korean.
Fast forward to 6 months later: my brother had outgrown me by a foot, a whole fucking 12 inches. He also gained a lot weight and muscle without lifting weights. His whole bone structure seemed to have expanded and compounded. His hair, nail, eyes, etc. also became more healthier. His mind also became more alert. The difference was evident.
See, what happened was, my father, concerned for my brothers health, forced him to exercise and follow a strict, healthy diet. I believe nutrition played a huge role in his transformation, but I think the change would not have been so great, had it not been for exercise. My brother was ordered to jump 200 times 6 days a week for that 6 month period. And I mean, leaps, not your short basketball 3 pointer jump, but your get low and explode with full power to dunk type of jump.
Fast forward to college: after years of sports, my brother was around 5'10, and I (having lived in the US longer) was 6'1. Our parents are 5'2 at most.
So, jump - no, leap, with all your might. You're only 15. You'll pass the 6ft mark, no worry.