My Grandmother is buying me the Gazelle?

My mother is going to be buying me the Gazelle from Tony Little for the summer seeing how I just recovered from a broken knee and the impact of stepping down onto the pavement irritates it. But it has a weight limit of 250lb. I weigh -on a good day- anywhere from 280 and 300 -on a bad day. Will this be a serious problem? Or not. I just want to know if I step on it will it roll up and snap like a 4th grade art project using paper, tape and tooth picks.