Can children sense pregnancy?

So I’m a nanny for a few little kids. The youngest is 4 years old. I’m about 5 weeks pregnant and I have not told anyone but my fiancée and his family. This little girl is sitting on my lap and starts touching my tummy and telling me that’s where my baby is. I thought it was super odd and I asked her what do you mean, that’s where babies grow? And she said there’s a baby in there right now. I know it’s pretty wild but I was wondering if anyone else ever had any odd experiences similar in that kids knew about your pregnancy?