Astoria was a seventh year, an actual one, not whatever Draco and his cohort were.  Despite her and Daphne being sisters, they were opposites in many ways.  While the facial structures were similar with delicate noses, sharp cheeks, and slim jaws, that’s about where it ended.  Daphne had blonde hair; Astoria had jet black hair.  Daphne had the capacity to be kind and think for herself.  Astoria had only aspirations that her mother had given her, and Merlin help any poor soul who stood in her way.