It is true that you are in a growth period. You do not compare your penis by looking at others penis. You cannot judge the length just by seeing. When you see other's penis, you are seeing it from a different angle and you see your penis from the upside. This makes a lot of difference. You start thinking that yours is smaller than others.So do not compare and do not worry about it. keep a well disciplined life and enjoy growing.
Your penis will grow naturally on its own, and at your age, you are still growing in several areas. Just try to be healthy overall by eating proper foods, including breakfast, and do a proper amount of exercise through the week.