At your age I wouldn't worry too much about it. The advice the guys are giving you is good. Start lifting heavy and get as big as you can before worrying about too much body fat and getting cut. Same thing goes if you want to compete. Give it time, learn more about training and what type of workouts work best for your body. You still have a few more years to reach your max height- its easier to gain for shorter guys than tall guys, so for now take advantage of it.