You need to iron the sheet! hehe. Seriously though it is a bit distracting so moving your model away from the background would help blur it. Love it apart from that.
I know there's a time limit to each challenge but surely you had enough time to iron the background or at least hang it (preferably wet) a day before so the creases can straighten. I can't see what she's holding in her hand, is it a hockeystick?