I'd suggest something a little bigger, maybe a 125. I was 16 years old when I got my KLX 650 thumper, and I grew into it. An 85 is a little small, and eventually you'll need more power.
Also, unless it's street legal, be careful riding to your friends houses. I got into big trouble when I was younger for riding without a licensed vehicle, even though I was riding in the ditch next to the road!!