be honest or let him do his thing??

so my guy friend has had my phone number for a while now and we text each other at, right? so he recently told me he has a crush on me. I didn't know what to say, so I said I felt the same. so we sit next to each other in like, every class, and now he's doing weird shit. he's rubbing my arm/elbow cuz he says my shirt is soft. he also rubs my leg like all over under the table (inside of my thigh, my knee, the outside of my thigh, kinda by my butt). it makes me really uncomfortable sometimes, sometimes I don't even notice it. we're really good friends, so I don't wanna mess it up by asking him to stop. he asks if I like it, like all the time, and I say no, but he keeps doing it.

I'm thirteen and I haven't even had my first kiss. I don't want it to be him.

WHAT DO I DO?????