Punishment for throwing paintballs?

Hello, I am a student at a local school, It was the third to last day of school when a friend of mine found some paintballs under his bed... He asked me if I wanted to throw them, I said yes. We went to the top floor of the dorm and threw them at the sidewalk and road. He then started targeting cars and told me to try it. I hit a dump truck, (at which point I stopped) while he proceeded to hit several more cars. He hit a staff member's car and they pulled in. They informed the Dean, and he came to the dorm to reprimand us. The next morning when we met with him there was a police officer there as well. The officer told me that I would receive a negative mark on my juvenile record (I'm 15) and I would probably have to appear in court. I was also put on DP (disciplinary protocol) Which is a punishment for bad behavior. I was the top 3 in my freshman class, with full marks for behavior and attitude, I'm on varsity Crew, and I've never had to be disciplined once, and now I'm facing court. I totally admitted that I understood I was wrong and that I had a serious lapse in judgement, and I'm truly sorry for what I've done. I'm ashamed of myself... I have tried my utmost to be a good student, and now it's all tumbling down. What should I expect for a sentence? I really wouldn't mind community service, actually, I'd be happy with it. But I would die if I had to go to juvenile detention... Please, tell me what I could do to appease the people I have harmed and angered!? And will the judge take into account my previous good behavior and realize that this is not a pattern?