Answer
Try it and see. As you try to stand on the balls of your feet (i.e., "on tippy toe"), your support base moves toward the wall. Your CG doesn't move much horizontally, and a vertical line passing through your CG extends beyond the area bounded by your support base.
The wall prevents you from shifting forward to keep your CG over your toes, and the torque produced by gravity tends to topple you backward.
