Diana was thirty-six years old when she died in 1997.
She married Prince Charles.
She was a Princess because she married Prince Charles and she was of Royal blood. She was a Lady. That's the best answer this American can give off me head. Any Brits know better? Diana was not of...
Diana, her title was never Princess Diana, was the Princess of Wales
The title was one she gave to herself. This was then promulgated by the popular press.