She looks young, but her hair has already turned mostly gray.
Lucretia and Jessamine's mother died a few hours after giving birth to Lucretia, leaving the twins to be brought up by their father. He wasn't quite equipped for raising children on his own, but he doted on his daughter, and she grew up strong and healthy. She never learned many social skills and never learned to watch her mouth growing up either.
Their family is Lower Upper Class; the siblings took to martial training and never looked back.
Note: Their father had a brush with death in the children's childhood. The story he tells involves fighting a dragon.