Gymdandee made a great correction for me. I really meant to say resistance training under careful supervision. Thanks, Gym.
Eat a healthy diet and you need to be careful on your strength training as your still growing and your growth plates could be compromised! As paxiled said you need to be supervised on the training.
At your age I wouldn't use any supplements or high protein diets that I'm sure everyone on here will recommend. Just work harder on your weight training, under supervision, and get nutrition guidance from someone with expertise. But again, you don't want to mess too much with a balanced diet at your age because you're still developing.