Making these for a friend’s 9-month-old daughter.

The pattern claims to be written for a chunky-legged 1-year-old, but the circumference doesn’t seem nearly large enough! I’m using the cast-on edge, which is supposed to be at the top, as the bottom edge, and increasing as I work my way up the leg, so that these have a chance of fitting around Alice’s thighs. I’m wondering if the sizing difference is due to the cotton-blend yarn I’m using, because it is less stretchy than wool?

(Note from Alice’s mom: ‘Looks like 10” circumference. Thickness roughly 4” .’)