18weeks baby - how much do yours weigh?

Katie
My little girls 16lb 4oz and my SIL just said "don't worry when she gets moving she'll lose the chub" am I right to be a little pissed of at this. She's breastfed and was always told they can't get fat on boob milk. She eats approx8 times a day and sleeps through the night so no feeds between 10pm-8am.