Jumping a generation

I received a charming Valentine package from my family in Spokane today.  As I was opening the package and reading the hand crafted cards I was thinking "ah, yes this is from my niece and nephew."  Then I looked more closely and realized that this package was from my great-nieces and great-nephew.  How can that be?  The last time I saw them they were just babies, now they're crafting and signing cards?  Life seems to speed past when I'm looking the other way, but it's such fun to watch the family grow.