Possible Clues:

• Longest-living First Lady in U.S. history
• Honorary president of the Girl Scouts from 1945 to 1953
• Attendee at the Medicare signing ceremony
• First Lady of the United States from 1945 to 1953
• 'A woman's place in public is to sit beside her husband, be silent, and be sure her hat is on straight' speaker
• '40s First Lady