Baby underweight? People keeps commenting on baby size.

My baby girl is 5.1kg at 16weeks original pd mentioned she is underweight and have to take apeton to up her weight. But we visited another pd and he said baby growth is normal and not underweight. Baby is on full bottlefed bm but doesn’t like to drink much milk and drinks about 590-620ml per day. But first pd said baby should alr be drinking 900ml per day. Although second pd say anywhere between 500-700ml per day is okay. Baby is very happy and hitting all her milestones well, in fact she is hitting her milestone faster than her age. But people around keep commenting on her size and it makes me very stressed out and angry. People keep asking why she is not chubby despite being on bm and it’s getting very annoying. She still have rolls on her arms and thighs but just not very chubby. It is normal? #adviceplease