Life fast forwarded

It doesn't seem so long ago that I was living with my 2 girls in Shilo, watching them grown and develop... maybe that's because it wasn't so long ago!
It's hard to believe that less than a year ago the younger told me she was getting engaged.  It was so exciting, and it happened so fast. Within 3 months she was getting married.  And in the meantime, her older sister told me she was also getting engaged, and we had her vort a couple days before her sister's wedding.  And she also got married within 3 months, and just 3 months after her sister.  And now they're both pregnant, one due in a month and a half, and I'm about to be a grandmother! How did all this happen so quickly?
I'm still internalizing the wonderful fact of their being married. Don't know if I'm quite ready to be a grandmother. And the one nearly due wants me at the birth... that will be quite an experience, amazing, but I think also hard, seeing my daughter in pain. Of course it will drive home the fact that it's really happening and I'm really becoming a grandmother.
Aren't I young to be a grandmother? I have friends with kids in kindergarten...