Rude people rant

I'm 35 weeks and I think I'm pretty average size for being this far along. Well last night at my sons art show, some lady I've never met before came up and asked how many babies I was carrying. I told her just one baby girl to which she responded "wow you are way bigger than I was and I had twins" - seriously?! I was so mad but ignored the comment as it was my son's school, but come on how come people think that's ok to say?