a teenager is really tough. It's the where you have to deal and cope with the most changes, in your whole life. This transition from childhood to adulthood is smooth for some, but rough for others. The most important thing about being a teenager is responsibility. When you're a teenager, you get blamed for anything wrong you do, get grounded, punished, unlike before when you were a child, and you could get away with murder, and nobody could do anything about it! You can say goodbye to those days now!
It's all not so bad about being a teenager though. Now you don't have to have your parents take you to somewhere you want to go, and somewhere you couldn't go before. You can go with friends and have fun, which you couldn't because all of you were too little to know what fun is! You can now go to amusement parks, parties etc. with friends, or even alone. It's a very enjoyable time of life, if you do the right stuff, and put thought into what you are doing. But with all good things, must come the bad. During this age, you are old and hopefully smart enough to understand what is good for you, and make decisions without consulting others. But with that comes risk, and nowadays, fun stuff are usually bad stuff.