I'm just start out ride like two weeks ago. My boy tried to help me. I can ride the bike but my not right to stand up like he tells me to on the bumps on the field. How long should I wait before starting to stand up??? The only time get to ride is on the weekends. What kind of bike should I buy or start on? I'm 5'4" and about 145 lbs. Right now I ridding a bike that my boy has around his place.