Ended up in Detention! :( High School Girl Needing Advice?

Okay, there was another food fight at school. Me and 3 other people kind of stayed stunned while everybody ran like animals in a stampede trying to take cover from the food. When the principal came and the bunch of security guards we were there like in the middle of the cafeteria with the plates all over, chairs overturned, you know the typical food fight setting. They blamed it on us! Now we have to spend time in the stupid library while I could be in my 11th. pd. class Athletics and the rest of the 3 kids could be in their class too. And then this security guard that keeps on staring at me (and I think he stalks me) gave me a dirty smile. :( I was so pissed off. I even told my parents but they said "well things happen for a reason". :( I mean, I didn't even take part in this event and I get blamed and humiliated for it. Now I have to spend time in the library on a table with the 3 people and the principal told us to stay there or we would get in serious trouble. I mean one of those is a nerd, the other a goofy guy I don't talk to, and the other is a fellow athlete I do talk to. So Help Please! Should the 4 of us team up and talk to the principal and the securities. What would you do in my situation??