Is my female Amstaff too small for her age?

She is 9 months old and about 17 kg (37 pounds). Should she be larger at her age? And how long do Amstaffs grow? I've heard the grow about two years but not sure. Otherwise, she looks fantastic and I feed her very well, with meat, intestines, and high quality kibble.

I wanted to show an image but Reddit doesn't allow me for some reason. She's a very beautiful girl.