It is commonly believed that teenage years are the best period in our life. I definitely agree with that statement.
First of all, being teenager means that you aren't already a child but you aren't an adult yet. It is time when you can try some real, adult life but you can also have a lot of fun as you are young enough to play.
What's more, teenagers usually don't have to work, they get money from their parents. It means that they have a lot of time to develop their hobby, try different sports, make new friends etc.
Some people may say that being teenager is boring because you don't have the right to decide about yourself, you have to ask your parents for permission for many things, and you are not allowed to go to some places. That's true but I think teenage life is still interesting enough.
To sum up, I think that teenage years, as every other period in our life has some pros and cons. However, from my point of view the advantages strongly overweight the disadvanteges.