Jenny is a very shy, timid girl who is generally not very comfortable in social situations, particularly when there's lots of people around, and hates being the centre of attention. Usually in social situations she will be on the outside of the group looking in, and will generally not actively engage in conversation with someone unless spoken to first and often isn't hugely talkative even with people she knows. This isn't due to rudeness, just shyness. When involved in conversation with someone, Jenny speaks in a quiet manner and often with a stammer. Jenny is also uncomfortable with physical contact of any kind, even just being hugged, and often doesn't know how to respond to this sort of contact. This is due to the fact that the only physical contact she has ever known is people being mean to her. Similarly, she is naturally distrustful of other people, often believing that they intend to cause her harm, again this is not due to rudeness but stems from her past experiences. Despite her overwhelming shyness, Jenny is at heart a very kind and caring person.
Jenny's parents were murdered when she was very young by Deatheaters due to their strongly pro-Muggle views (though Jenny does not know anything of her family history). Her parents (and thus Jenny) were neither Muggle-born nor half-blood, indeed Jenny's family on both her mother's and father's side is actually strongly pure blooded. It is a result of this pure blood lineage which made Jenny's parents views particularly galling to the advocates of magical purity, eventually resulting in their murder. Jenny survived but had no other family. As a result, Jenny spent her entire childhood growing up in an orphanage along Crete Road, on the outskirts of Folkestone in Kent. Growing up in this orphanage, Jenny had no proper friends whom she could trust although there were one or two people with whom she got on okay with. She spent most of this time trying (not always successfully) to avoid getting beaten up or otherwise picked on by most of the other kids in the orphanage. Being small and timid, Jenny was often on the receiving end of the punches and hits of the other children in the orphanage. As a result, her body became a patch-work of cuts and bruises, and crying herself to sleep while nursing a new injury was a regular occurrence for Jenny.
The orphanage itself was overcrowded and had limited resources and facilities, small uncomfortable beds, limited heating during the winter and little in the way of entertainment. It was during this time that the first signs of magic appeared, though Jenny had no idea what it was. On occasion unexplainable things would happen in her presence, though this just made her more of a target to the other kids. As a result, Jenny began to resent the fact that all these strange occurrences took place in her presence which led her to be branded a 'freak'.
It was on one overcast summer day, as she was lying in her bed in the empty dormitory that she shared with 9 other kids gazing at the ceiling, that an owl swooped in through the open window and landed on her bed, dropping what turned out to be her Hogwarts acceptance letter. Thinking it was just a prank of some kind, Jenny initially ignored it but rather than throwing it away, she kept the letter hidden under her pillow. Over the course of the new few days, Jenny began to think about all the unexplainable things that would happen in her presence which made her begin to wonder if there was more truth in the letter than she might have first realised.....
Jenny's first few days at Hogwarts were a whirlwind of new experiences and discoveries. Having no real experience of the world of magic, everything was new to her. Despite this, Jenny had a strong desire to completely immerse herself in, and become part of, this new world. As a result, she very quickly adapted to this new environment. In her first few days at Hogwarts, she spoke with few students, she did however spend much of the time simply listening to her fellow students, picking up various magical words and phrases. In addition, she spent much of her spare time in the library reading about the world she was now part of. As a result, Jenny already has a quite a bit of knowledge about the world of magic.
Jenny has been taken by surprise by the attitude of her fellow students at Hogwarts. Against Jenny's expectations, the students seemed both pleasant and friendly. Nevertheless, Jenny remains very shy and is reluctant to engage in conversation. As much as she is enjoying the new environment of Hogwarts, deep down Jenny believes it's only a matter of time before she encounters the same hostility and violence that she experienced at her orphanage.
As a student, Jenny is not particularly academically gifted but is exceptionally hard-working and is extremely dedicated in all her subjects, even those that she doesn't particularly like. Due to her shyness, she is unlikely to ask a question in class even if she doesn't understand the topic at hand. In the event of not understanding a particular topic, she will likely wait until after class and then consult a book. She is, however, particularly good at herbology and potions. During the summer months, Jenny would often spend as much time as possible outside, in the grounds of the orphanage where she was resident. As a result, she gained an increasing interest in the flora she would come across, this meant she found studying the magical properties of plants particularly interesting (even if most of the plants studied were not ones which could be found in the grounds of the orphanage).
Despite being admitted to Hogwarts, the orphanage remains her 'non-term time' residence and she returns to there each holiday, as much as she hates it. Jenny tries to keep the fact that she lives in an orphanage secret to everyone she meets at Hogwarts. She also tries to hide the fact that she is a witch and that she goes to Hogwarts from the other kids in the orphanage, if questioned about where she goes during term time, she would merely reply "a boarding school up north".