Daughter talking about a baby in my stomache!!

Ok so I thought this was so crazy!! Just wondering if any of your kids has said anything like this to you before? FYI we haven't talked about having more babies around her. I sell kids dresses as a part time "job" I was putting my dresses in bags bagging up since I sold them. My daughter that is 3 was in the room with me the little sizes she asked why are you selling those I said because I don't need them and your to big for them. She said I want them for my real baby meaning a brother or sister this is the second time she's brought up baby stuff the first she told me she wants a brother and sister. I said you don't have one she said I want to go buy one I said it doesn't work like that I would have to have one in my tummy I asked her where she got all of this from. She says you have a baby in your tummy!!! Of course I told her no I don't lol. My husband and I have been trying for our 3rd baby for two months and don't talk about having more around our kids or any of that so I thought it was crazy that she came up with that whole thing wonder where kids get these things from.