What should i do?

i'm 15 and i was arrested for a crime i didnt commit. The prosecutor offered me 30 days in girls juvy if i plead guilty. If i don't and i go to trial i could lose or i could win. the problem is the prosecutor got the 2 people who really committed this crime to take a deal. The 3 of us used to be really good friends but they got into drinking and crime and i stopped being friends with them after that. There very angry at me and now there going to tesify against me to get back at me. if I accept the deal tommorow then I go to girls juvy for 30 days right away. If I take the deal I'll have a sealed criminal record which no one will be able to see. If I dont im looking at over a year if convicted. do i take the deal ? Plz help.