BezionerGirls Ballet Wrap Skirt Women Chiffon Dance Costume With Adjustable waist tie

The size is the length of the ties I believe so how big is the actual skirt ?

Is this a child’s or adults skirt?

Is the measurement the waist size? I'm looking for a size that will fit my slim 8-year old. Thank you!

Can you suggest a size for a 8-9 year old please. She has a 68cm waist