I think I need a new bike?

I'm 15, five foot nine and I'm still riding this bmx i'v had scince I was like 12 and I think I'm out growing it, but I HATE mountain bikes and don't want one. Is there a bike that doesn't had all the gears of a mountain bike, that's bigger then a bmx and isn't a bike for just cruising around because I still like to go fast and into the nearby forests. It's a mongoose pro mischief: a href="http://bmxmuseum.com/bikes/mongoose/29462" rel="nofollow"http://bmxmuseum.com/bikes/mongoose/2946…/a