The flip side is that if she fails...she fails...but it isn't fatal. When she gets to repeat a grade (or is forced into Summer school to make up the work) because of her own doing, it will sober her up fast.
Sometimes you have to let the small disasters happen now to avoid the bigger ones later.
I call it 'controlled failure" and I let my daughter experience it regularly just so she gets the concept that the net isn't always there...so she better pay attention to what she's doing on the high-wire of life.