It's also important to remember that "popularity" is a subjective concept and can vary greatly from school to school and even within different social groups within a school.
Instead of focusing on popularity, perhaps it would be more interesting to consider what aspects of her life and experiences may have contributed to her eventual success as a writer. For example, we know she was a voracious reader from a young age, and she wrote her first story at age six. These early interests may have been more influential in her career path than her social standing in high school.