At your age you shouldn't need any supplements, just eat a good, varied, diet, and you'll get all the nutrients that you need from that.
Whatever you are doing it's best to get all you need from good fresh food. If you take supplements you have no control over what you are putting into your body. Not only can there be harmful ingredients, but if you get to depend on them there will ne components missing that your body will need.
There is no supplement that you can buy that has the range of vitamins and minerals that you get from a varied diet, and since you are still growing that is an important fact to consider.
