I had mine when I was 10, so not the same thing, but it wasn't that long before I was back to activity. I wasn't at Piper's level, obviously, but I was in serious ballet training at the time. If I remember right, I was out fully for two weeks and then eased back in for awhile longer. As long as hers didn't rupture and need major surgery, it shouldn't be that big of a deal. Yes, she'll need time off, but good physical therapy should get her up and running again before long.Ah isn't appendectomy pretty serious and very hard on the body especially flexibility?