The only bike frame I ever broke was steel. I weighed 170 lbs at the time.
Ride it. The wheels are much more likely to be the weak point than the frame. Don't huck it or try to get airborne and you will be fine.
The weight limit is there for the warranty/liability. If you do break the frame when you are over the limit, it probably would void the warranty. So if you can live with that, ride the hell out of it and soon enough you'll be under the limit. (Actually, watch your diet too. Riding makes me eat like a pig.)