I bought these for a 3 year old and a 6 year old. Both of my girls are above average so I always go bigger and I did that for them too. The legs fit both perfectly, but the waist was a bit large. I ended up rolling my waist up once for both kids (similar to how you sometimes roll up your pants). They also have belt loops, so that's an option too if you run into this problem. Both of my girls ended up loving their new "jeans" and wanting to wear them non-stop all week.
Comfortable and π Versatile Amazon Essentials Girls' Sweatpants
39 Review
Girls' Straight Leg Pant by French Toast
32 Review
Premium Organic Cotton Girls' Clothing by Hope Henry Riding: Sustainable and Stylish Fashion
33 Review
WDIRARA Girls' Clothing: Multicolor Snakeskin Print, Casual Stretch Pants & Capris
49 Review