Do not underestimate the power of food!
Nutrition is one of the most overlooked aspect of a young athletes life. I cannot overemphasize the importance of a good diet (especially in young athletes). There are many myths and beliefs when it comes to feeling a young athlete most of which are false. The first being that young athletes are so active and have such a high metabolism that they can eat anything and just burn it off. The second leading to an over use and misuse of supplements to cover any shortfalls. Both of these fallacies will dramatically shorten the already short timelines of a young athletes career.
With the advent of the internet there is an abundance of information at your fingertips. An over abundance that would confuse and mislead even the experts. Be very careful where and who you get your information from. Much of the information available is so far outdated and biased by companies pushing you to buy their products. Make sure your research comes from reliable unbiased sources (do not rely on your doctor as most doctors know very little about nutrition).