I was called chubby by a little girl today

I was at the grocery store and there was a mother in one of those sit down scooters going around the store. She was probably 350-400lbs. I got stuck right behind her in an isle because she couldn’t reach down to pick something off a bottom shelf. Her daughter was saying “there is someone behind you.” But she ignored it. 10 more seconds went by and she still couldn’t grab it. I stood there patiently, but got pretty irritated I must admit. Then the little girl says “there’s a chubby girl behind you.” I’m not fat by any means. And I wouldn’t really call myself “chubby” especially compare to her mother!? Like wtf. Why would she say such a thing?