Old Navy Size 16 Denim Button up skirt

On trend denim Old Navy button up skirt size 16. The skirt is probably 99% cotton, 1% elastane, or 100% cotton but there is no material tag. There is no stretch and it fits more like a size 14. Laying flat the waist is 18" across. The length is 22". There are no visible marks. It's been in a smoke free, pet friendly home.