Jen is a middle-aged woman.
Jen has a type of independent/self-sufficient personality, as she doesn't get captured by William, that may tell us she can fight back for herself.
Five Nights at Freddy's Novel Series
The Silver Eyes
After the murdered of Sammy, Charlie's twin brother, when they were both toddlers, and the death of Henry. Charlotte went to live with Jen in Utah.
Aunt Jen is what Charlie refers to her aunt as. While Aunt Jen is never present in the book, she is mentioned in several flashbacks and is described often by Charlie. She seems to be a strong woman, able to take action when necessary. She puts emphasis on things Charlie should do to be well-prepared for any occasion as well as expects her to be mostly independent. It is never stated which of Charlie's parents she is a sibling to, though it can be assumed it was her father as Jen has ownership of Charlie's old house and the property it's
Fight with Charlie