I don't know what to do with this guy...?

I'm 13, he's 12. He's sort of my half-friend, more an acquaintance. We're both really short and skinny, he's a little heavier and taller. I'm 4'11 he's 5, i'm 62 pounds and he's 70. Anyhow, there was this one time he was being annoying as usual to me. See, he always trys to get himself to seem better then me. I was ignoring this crap all day, but this was the limit. We were on my friedn trampoline and I grabbed his basket ball he was trying to show off with and beaned it at his head. He then called me some names I can;t say and tried to punch balls. So I tackled him and punched him a few times and tried to make it seem like it was nothing to him. He was saying stuff like oh wow and all that, but it was in a squeaky voice. i then brought it to the ground and he elbowed my face. First off, he makes it seem like he DK punched me but it was an elbow with 4 pounds of force. He hit me in the nose so my eyes started to water and then my other friend david grabbed us and threw us apart. Then today, for some reason he started bragging about this and started sying how he 'kicked my a$$' and how i was crying. I guess i was but it was because he hit my nose. Please, i'm not trying to be high and mighty and make me sound like a jerk, but this guy is really pushing it. help