I guess I'm getting old

I just had this real life conversation with my 4 year old after we saw a video clip of someone's birthday party -

Me: Do you know who has the next birthday in our house?
Nas: Um... who?
Me: Me!
Nas: Why do you want to be a grandma?
Me: A grandma?  I'm not old enough to be a grandma?
Nas: Why?
Me: Because I will be a grandma when my boys grow up and have babies.
Nas: But I have a baby, Maru the cow.
Me: So, he's my grandson?
Nas: Yes!

There you have it - I'm officially old.  I have my first grandcow.