Little girls pants 2 pair

The grey pants are a size 8 from old navy and the black ones are a 6/6x HOWEVER, they are the same length. The black ones have a draw sting (my daughter is super skinny so they may look smaller in the waist in the photo). Old Navy pants (for little girls at least) tend to be a little smaller in the waist I’ve noticed. The grey ones have a small stain on the leg