My question involves criminal law for the state of: Michigan

My names Amanda and I am only 17 years old I got caught shoplifting from JcPenny's and I have already started a payment plan with the store its self. They told me if I could pay them the money that they would not go any farther which involved court. But I got a notice to appear today in the mail and started flipping out. When they caught me they said I was legally an adult but on all the papers I received from so far has said minor on them. My parents know about it and where mad when they found out the store did not call them.

This is how the incident went. I took a ring worth 45 dollars and was stopped by the LP's, the man was extremely big and scared me half to death. I immediately throw the ring off off my person and they did not find it. They took me to the back room and keep asking me where the ring was and I told them I threw it but they didn't believe me and thought I gave it to one of my friends. When my father called to ask about the incident however the man told him that he seen me throw it from my person, when he didn't. He keep asking me where it was and he even said "why would you steal something then throw it away?" I signed the papers and was let go. The cops where called but I never seen them because JcPenny's was impatient and just let me go.

My dad is telling me to plead not guilty because they did not fine the merchandise but I don't know if I should take his advise. I'm scared and don't really know what to do. I'm an honor roll student and I have never shoplifted before in my life. I have no record will that help at all? What should I do I know I'm guilty but my dad says they can't prove it...