Welcome to SS. We'll be glad to answer some of your questions. The best advice I have for you is to read, read, and read some more. Find an area that looks the most interesting to you. Read all you can to find answers to your questions. The time to ask questions, is when you have exhausted all other means of finding the answer. That is the SOF mind set, and what is expected.
Never forget that this is the time to explore, make mistakes and learn from them. You do that by having fun as a teenager. Play sports, and have the best time can now. There is plenty of time for the other stuff later.