These screenshots are taken from a video web site. The girl is dancing, but her butt can be seen.
Most Helpful Girl
It's not that it is too short, but more of the skater style skirt. Those don't sit close enough to the body so when they move they are more likely to show more
Most Helpful Guy
it looks like a costume for a performance and not a skirt she would wear everyday, so who cares if it's short or not