The author has started thinking more about his parents' aging as his kids grow up.Maskot/Getty Images/MaskotMy kids are getting older, and time is going by more quickly. I didn't realize parenting would make me think so much about my own parents.As my kids grow up, I've been thinking more about my own parents aging.I didn't expect my kids getting older to make me think so much about my parents.When my kids were little, my wife and I were consume…