Caroline Kennedy, turns 50, is 'Cover Girl' for AARP's Magazine

"Ever since I was a little girl, people have told me that my father changed their lives, or that President Kennedy's inaugural challenge, `Ask not what your country can do for you; ask what you can do for your country,' inspired a generation in the 1960s that transformed our nation with courage," she told the magazine. "To me that is one of his greatest legacies. Now, it is up to us to redefine that commitment for our time."