Big Baby.

There are perks to being friends with people older than you, like when they can get you into that R-rated movie (that totally shouldn't be rated that, by the way) (I'm talking Grand Budapest Hotel), when they can provide car rides to the city for you so that you don't have to go with your mom, when they offer you sage advice on how to pass the SAT's.
Then, there are the pitfalls to having just turned sixteen when everyone around you is seventeen, eighteen. They're walking into local coffee-shop shows with confidence, while I stand in the corner like the big baby I am. They're going shopping with the money they earned from work, when you're not old enough to get a work permit. They can wrap their minds around high school, when you can't. Some of these are due to age, some are due to emotional maturity.
I am sixteen years old. My face is eleven, my body is twenty, my speaking voice is fourteen while my singing voice is seven. My maturity is twelve.
Being one of the youngest ones in your grade isn't fun. You're treated as the innocent child even though you are sure that is not the case. You have secrets kept from you because you're "too young to handle them." You're left out because maybe they don't want a kid around them. You're the little sister to the group.
Since you've earned the title, maybe you turn into it. You're completely dependant on other people and obviously you cannot function for yourself. The fact that you're graduating and expected to live on your own in two years makes you shake down to your core because the world is a very dangerous place, but you get mad because your parents wont let you ride your bike in the woods at night.
This is why I'm really just a big baby.