okay, I've been trying to start to do standups, but i have a problem. It's very uncomfortable when i stand up on the bike. it feels way too unstable to start popping wheelies when I'm up there. Is this just a normal feeling at first? how do you get use to it? I'm 6'1" and it feels like the bike is tiny when I stand up. should I just find somewhere and stand up and ride around like that for a while or what?