I ordered 10 Slim for my 9 year old daughter. She is very slim but tall. While her waist can fit a 6/7, she needs a 10 for the length. They are slightly larger than some of the 10 skinny pants I've bought from other stores. My adjustable waist is as tight as can be and they are still large. The legs are definitely baggy too. And the length hits her heels. Even though they're bigger, she said they're comfortable and soft. Overall I would buy them again but I'll try maybe 8 to see if they fit the waist better and are still long enough.
Thermajane Girl's Cozy and Comfy Thermal Underwear Long Johns Set with Fleece Lining
46 Review
Dancina Toddler Leotard Flutter Sleeve Girls' Clothing for Active
55 Review
Eocom Pairs Childrens Winter Animal Girls' Clothing
64 Review
Amazon Essentials Little Short Sleeve Leotard Girls' Clothing for Active
61 Review