I'm not sure what you mean, what doesn't matter? ... You dropped it?

Anyway, what I was going to say is, as the waist is tight up to her body before the drape and too far from it afterwards, you might have accidentally scaled it after a previous drape and created an unwanted scaling keyframe.  Check that you haven't accidentally added a ketyframe for the scaling of the skirt somewhere along the timeline, and if you have, delete it, go back to the first frame on the timeline, then ensure the waist is as tight as you want it before you drape it again.