Hi!
You can publish no matter how old or young you are. With your age, you’d have to have parental permission to publish (as you would need for any legal contract until you’re an adult), but it’s certainly possible.
But! I want to make sure you know that publishing now…it’s just not that important. I was writing when I was your age as well, and I dreamed of publication, too. But now I am so, so, SO glad that I waited to seek publication. Right now, your job is to grow. Grow as a person, grow as...