My parents wont let me date and I have a problem?

Well um im 13 and my parents wont let me date til im 15. Well errr i sorta went behind their back and dated this really good guy, but his mom accidently found out. Im worried she will tell my mom and if she did I would be in major trouble because they said if they found out I was dating they said they would take my laptop and phone away for a year. I'm going to break up with him, because I know it was wrong and I am really guilty for going behind my parents back. But I really need to make up a story or something so his mom wont tell my mom or my mom will tell his mom it was just a misunderstanding. Please help!