You're still pretty young..now is not really the time to be doing a restrictive type of diet, at your age just make sure you are eating healthy and are active and your body should do the rest for you (read the stickied posts in the nutrition and exercise forum). Normally, to lower body fat% while retaining muscle one has to be dieting and lifting weights, but at your age since your body is growing fast lowering your calories is not a good idea at all. What I'm trying to say is since you are so young if you eat healthy and stay active your body is going to burn off all that fat you don't need anyways. No need to wait to strength train by the way, just make sure you have someone show you the ropes so you don't injure yourself. Do it right and by the time you're in university you're going to have a pretty awesome physique.
