Alzheimer's and babies

So my mom told my grandma I was pregnant today. She has Alzheimer's. My grandpa said for the last 3 weeks she kept taking about me saying it's my birthday. My birthday is in June. And she's not that far gone enough to think that my birthday is now, when her only 2 grandchildren have summer birthdays. A little less then 3 weeks ago I had the ultrasound. Anyone think my grandma might know? I think so! A little spooky but it makes me wonder!