You are 15 and know a lot? Fitness and nutrition has honestly been my number one passion since I was 10 years old. I eat, sleep, and breath this stuff! And trust me, I am not alone.... there are many on this board that walk my same path. And you probably love it as much as I. I am not questioning this.
However, if there is one thing I have learned about bodybuilding, fitness, nutrition, and health in general, the education of these things is never-ending. Science and real world data is ever-changing. Breakthroughs are happening at lightening speed. New philosophies are being introduced almost weekly.
On top of this, our bodies are finely tuned machines. They adapt to anything we throw at it in the sense of training AND nutrition. Therefore, our search for the proper techniques for us personally, is also never-ending. We should be experimenting constantly. Core fundamentals should always remain intact, but that is only the backbone, there is so much more.
Listen, if you really want an education, do some reading over on the forums and articles of
www.t-nation.com. I guarantee that the amount of in depth, scientific articles there will make you feel like you don't know a thing! You will have the chance to read articles from some of the most advanced and best physiological scientists and sports nutritionists in the world FOR FREE. You will find these in the articles section of the website. Their forums are also very useful.
Reading is another passion of mine, and at the age of 15, I promise you have not read enough. If you need ideas for some books, PM me and I will give you a list of quality readings.