I don’t know how to tell him no

One of my friends in summer camp has recently asked me out. Being thirteen years old I feel like I am NOT ready for any sort of relationship at all, plus my parents definitely wouldn’t allow it. Also I’m not romantically interested in him. So I just told him the part about my parents not letting me. Before this he asked if I wanted to go out but hadn’t explicitly said it was meant to be a date. I panicked and responded the next day saying I was busy, and that when he had texted me my phone had run out of battery. But this time he said it was a date. I told him that my parents wouldn’t allow me. He asked to hang out on weekends as friends and I said I was busy again. Keep in mind I see him THREE HOURS EVERY WEEKDAY at camp. I didn’t want to hang out because of this and also because I was scared that while hanging out he would try to talk to me about a romantic relationship. Now he keeps trying to hang out with me on weekends.

I didn’t think it would be awkward at camp because I thought he got the vibe and would therefore stop. I wanted this to come across as “I think of you as my friend but I see you a lot already.” But just yesterday he asked me in person. How do I tell him that I see him more than enough as it is without offending him?? Sorry for the long post.