Simplify the following text for a Grade 9 native English-speaking person.
Original: She was one of modern Japan 's most commercially successful and prolific writers , specializing in serialized romance novels and adolescent girlsâ fiction , as well as a pioneer in Japanese lesbian literature , including the Class S genre .
Simplified: She wrote many romance novels and adolescent girlsâ fiction . She was also one of the first writers of Japanese lesbian books , including the Class S genre .