Any one else have a small/petite baby?

I'm getting so sick of everyone telling me how tiny or small my baby is. She's 6 weeks old and 8.5 lbs. her birth weight was 5 lbs 12 oz, so she's up almost 3 lbs. I EBF and she's an excellent eater...we've had no issues with eating or with supply. It just makes me feel like I'm doing something wrong when people say how tiny she is and tell me she needs "some meat on her bones." Everyone mistakes her for a newborn and acts shocked when I say she's six weeks.