My question involves criminal law for the state of: New York

Two days ago i was caught trying to shoplift and item from Walmart with a value about $10. They brought me to a back room and once i was there they yelled at me for what i did and i admitted to it and told them how wrong it was and i apologized. I am only 15 years old and they told me nothing would go on my record but i would get a walmart record. I was unsure what she meant about this. Next she asked for some personal information me phone number address and name and asked to see my school ID. I did everything she asked but i never had to sign anything and the cops were never called. Next she called my parents to come pick me up. She told my parents i would be receiving a fine in the mail for five times the value of the product i was trying to steal and then she let me go. I was just wondering if any further legal action could be taken against me? Will i have to go to court or will i get a misdemeanor? I have heard so many horror stories about people receiving letters from law firms demanding hundreds of dollars. What should i do if i receive one of these? I was only told i would receive a fine for about $50 and i am really scared.
Also how long will it take for me to receive the fine in the mail.
Please offer any advice.