Hey man, be proud! It's still better than I could have done when i was your age xD *so old now lol*
I recommend checking out the school too. I wouldn't know what it's personally like in art school, seeing as I'm only in a state university, which is much more casual than an art college. But seriously, before you apply, go check the place out. Ask yourself if you can imagine yourself being there. Check out the dorms. The people.
Another big issue is tuition. Will you be paying for college yourself? Do you need to take on a part time job? Get some loans? Art school tends to be around 30,000 to 50,000 dollars a YEAR with tuition costs rising every year. If you're going to an art school, you need to be financially and personally ready for it.
The other thing is, anime is often looked down on in art schools, I heard. So if you make a portfolio to get accepted, try not to put any kind of anime in it (or at least limit yourself to 1 or 2 if you can't help it). The people overlooking your stuff get bombarded with anime all the time. Instead, concentrate on sending them various life-studies, paintings, crafts, anything that shows that you stand out and that you have a basic knowledge of form and realism. Attend a portfolio review at a local college to get some feedback, or even ask your art teacher. Spend time drawing realism and making black and white value studies. When you're actually in art school, you'll be doing this kind of stuff for the first year all the time. You'll be doing paintings the size of the walls of your room. It'll be fun, but challenging.
And a word of warning: Just because you graduate from an art school doesn't mean you'll get into the art career or even get a job. Like any college, Art school is just a TOOL for you to use. You can graduate, but if you keep to yourself all the time in college, aren't motivated enough, or you make a shitty portfolio out of it, then you've wasted your time and money.
I'm not trying to scare you, but it really is a big decision. Think carefully. I recommend looking at conceptart.org and check out their forum.