FILE - In this May 7, 2013 file photo, First lady Michelle Obama signs copies of her book "American Grown: The Story of the White House Kitchen Garden and Garden Across America" at the Politics & Prose bookstore in Washington. The nation’s first lady turns 50 on Friday and, by her own account, feels more relaxed now that President Barack Obama’s days as a candidate for elected office are over. (AP Photo/Susan Walsh)