Business principles is big I see, although my problem is finding what to revolve a business around. Maybe join a sales training job for the time being? Please help.. :/ I'm in it for the long run, I'm patient and persistent as long as the outcome will be positive.
Invest in two things: building skills and learn by doing. How you acquire skills depends in part on what type of learner you are (look up the 4 types online). Play to your learning style and learn. President Lincoln perhaps gave the best advice to someone who asked him how to become an expert in the law. Lincoln said "The answer is simple, but it requires work. Read, read, and read." The same applies to your situation: learn, learn, learn whichever way best suits you. Then put down the books, videos, classes and DO SOMETHING, TRY SOMETHING. By 16 I owned my first company, nothing big - an antique restoration business - but I learned about marketing, selling, assessing customer needs, negotiating, being organized, being focused, and working diligently. At 18, you do not have to invent the next Google, you need to be in business, learn to think like a business person, learn to make decisions like a business person. Good luck!