As a child model and actress, Brooke Shields became a superstar, but not much more was expected of her than to look gorgeous. Now nearly 60, Shields was recently elected president of Actors’ Equity, and launched Commence, her beauty brand for women over 40. She’s also written her fourth book, “Brooke Shields Is Not Allowed to Get Old,” which offers her thoughts on aging and on rejecting society’s constricting expectations for more mature women. Correspondent Faith Salie reports.