Lesley Stahl on the benefits of ‘Becoming Grandma’

You can’t know how amazing it feels to be a grandmother until it happens to you, says Lesley Stahl, longtime 60 Minutes correspondent and author of a new book, "Becoming Grandma." With her personal transformation, she began to investigate her own feelings and the vital role of grandparents today. Stahl joins Judy Woodruff to share her experience.