Once upon a time, a romance was just a romance, the story of a relationship between a male and a female that ended happily. Now romances are categorized. You can read about male-female relationships, female-female relationships, and male-male relationships. Or you can read sweets and inspirationals. Or you can read about threesomes and foursomes--even BDSMers.
Another dividing line is age, of readers and characters. The ages of the readers are categorized into "young adult" (ages twelve to eighteen), "new adult" (ages eighteen through twenty-four), and adult (default). Also, authors are expected to make their main characters' ages match up appropriately: a love story involving a forty-plus man and a nineteen-year-old girl such as Georgette Heyer set up in her classic These Old Shades could not get published today.
But Fiorella isn't sure readers care about categorization. A good story is still a good story.