Most people are focusing on your composition but I am going to take the other approach. I am just finishing up High School in the Houston,TX area and have gotten accepted into composition in college, and gone through many auditions over the past couple months (stressful)
The biggest problem I see you having is being proficient enough on your primary instrument, since you did not even play through high school. This is really your disadvantage since students coming out of high school have most likely progressed MUCH since middle school and since you put down your horn. If it is what you want to do then give it your all! I am not trying be arrogant in this post, I am just trying to point out some of the obvious disadvantage's you may occur (It is also generally harder to transfer into a music program, unless you are counting on entering as freshman).
Honestly, you can gauge yourself better than any of us can though (performance wise).
Best of luck!
- James