I was arrested for shoplifting?

I was technically arrested for shoplifting, but was not cuffed or taken to a police station. The place I shoplifted from is pressing charges, and I am not allowed into the store ever again. I understand all of these and that it will be put on my record, but I am underage, and do not have the money to pay the charges, and don't want my parents to have to pay them. How can I attempt to convince the store not to press charges? I am writing an apology letter, and am going to include it in there. Please, any help would be appreciated. I understand how terribly wrong I was to shoplift and am enrolling in a program and community service. So please I would appreciate if you didn't comment on this just to criticize me. I feel awful and any answers would be greatly appreciated. THANKS!