Yikes.... so many things that I am at a loss to words for how to explain.Be prepared to spend at least five years, maybe ten, constantly thinking about yourself a few years ago and thinking "what was I thinking? I was so stupid/uncool/childish/lame then... but I've got it all figured out now". I started thinking like that at about 13 and now (9 years later) am starting to not think like that quite so much. It probably means that you are learning from your experiences and maturing, but it's no fun being frustrated with yourself for a decade.On a similar note, be prepared to hear a lot of advice that sounds like utter rubbish, disregard it and then later think "I wish I'd listened to that when I was younger". (God, this makes me sound like an old git...)Learn to think. While your childhood years are spent learning to walk, ride a bike, write, construct complex sentences etc. your teenage years are spent developing your personality and your higher mental abilities. Every teenager rebels in some way, every teenager will have their own set of problems but if you can come out of them as a mature and responsible human being then you can call those years a success. While you may want to stomp around and listen to angry music, try to appreciate the niceties of boring "adult" interaction, because at some point or other you will be forced into it, and it's better to go willingly."Education is about making the inside of your own head a pleasant place to spend the rest of your life", and you will have a much better time as an adult if you learn to be independent and think for yourself. Try to teach your brain ways of having fun without relying on "chemical inconvenience".Yes, I know, you'll become taller and a different shape and have hair in funny places and all that but every kid knows those things- it's the change in shape of your brain that took me off guard, and you don't get a little educational leaflet about "So you're developing an adult personality?" in health classes.