Anyone else’s one year old

So my daughter is 1 years ild(dec 14th was her birthday), she weighs 18lbs but is 30inches tall. I’m always getting comments of how small she is, do you even feed her,that baby needs to eat more, etc. it’s extremely annoying. She was born 6weeks early at 5lbs 10oz, and had problems with breastfeeding, formula(she’s allergic to Milk and soy), she finally gaining like she should around 7months old , she eats everything we give her, and sometimes wants more. I’m also getting really sick of my mom comparing her to her other grand baby who is 5 months old and 21lbs. Sorry for the little rant but anyone else dealing with this? How do you deal with it