Apparently we're big

Today's encounter at Trader Joe's

Woman: So they'll be about 2-1/2 years apart, right?
Me (assuming she's talking about my children): Actually, they'll be about 21 months apart.
Woman: Really? How old is he?
Me: 18 months old.
Woman: Really? 18 months old? He's very big.
Me: He's tall for his age.
Woman: And that one (pointing to my belly) will be here in about a month?
Me (not commenting on the lack of math skills): Well, no, in about 3 months...
Woman: Really?
Me (starting to get annoyed with the constant incredulousness): ...
Woman: Are you sure? 3 more months?
Me: I'm quite certain.
Woman: Well don't worry. I got huge with my second baby too. And look how svelte I am now.