This song is particularly poignant to me right now, since this whole nostalgia kick that I'm on was caused by my noticing how quickly my kids are growing up. (And yes, I sat here and cried during the whole video.)
Granted, my story of parenthood didn't start anything like it did for the kids in this song. I was married, I was in my late 20s, and we did it on purpose. But regardless of how old you are, or how "ready" for it you think you are, having a kid changes everything, and turns you whole life upside down.
And it doesn't take long to realize how right he is about your kids being your life... your future... your everything.