I think it could be a close friend. A friend who has been through a lot with you would be able to capture the essence of your life. They know your joys, sorrows, and how you've grown over the years. They can write about the inside jokes, the shared memories, and the unique bond you have. Their perspective would be tinted with the love and understanding that comes from a true friendship.
Maybe a professional biographer. These people are trained to dig deep into someone's life. They have the skills to research your family background, your educational journey, your career achievements, and all the significant events that shaped you. They can present your life story in an organized and engaging way, making it appealing to a wide range of readers.