The task of creating your future can be daunting. It's hard enough to keep up with your studies, sports and social life. And now, as a junior or senior in high-school, you have to choose what to do with the rest of your life? Always remember, that every step in life you take, every choice you make will have a very big influence your future! So don't make any unwise decisions which you will later hope it never happen. You can enjoy yourself in high school, have fun with your friends, but don't overestimate the importance of boys, alcohol, drugs, just to fit in. Always study and work hard to get the best grades! You will thank yourself later when you get into an excellent university! Try to have a good GPA score to get a scholarship for your university trust me scholarships help you scholarship. Good old advise my mom always told me was, always be yourself and try your best if you fall down get back up and retry it until your satisfied.
I would tell myself to keep focused on what I want out of my life and not to get distracted.