This legging style by JAAM Apparel features:
Indulgent fit with yoga waistband.
Luxurious 92% polyester and 8% spandex blend.
Kid's l/xl ~ kid's 7-14 laid flat ~30 long total
This is an estimate, everyone's body is different. Take your best guess at what size you are and if it doesn't work out you can send it back for a different size or a full refund. :-)