Avery was once a sweet and loyal child, no doubt bound for the same house as her parents and brothers before her: Hufflepuff. But somewhere along the way, she got horribly mixed up. Every bit of energy she had once put into being nice and helpful, she now put into helping herself along.
Now, Avery doesn't hurt people just for the fun of it. To her, it's serious business. She simply does what is best for her at every turn - as much as is possible, at least. She keeps friends and confidences only if they seem of worth. If telling a lie or some horrible truth will get her further, then she will not hesitate to say such things, regardless of whom they hurt. On the flip side, she's also willing to be quite a willing ally and servant, even, if it seems it'll benefit her in the end. She has little shame when the ends seem to justify the means, and she is witting student of older housemates looking to mould her in their image.
Despite this hardened exterior, Avery is still a rather insecure child. But after a year at Hogwarts, being taught in the way of Slytherin, and appreciated for her synchophant tendencies by the older students, she's coming out of her shell, beginning to feel a lot more certain of herself. What doubt there might have once been if she'd made the right choice, most have been all but wiped away by the past year.
The girl's one weakness is her family. With two older brothers already at school, and two younger sisters to follow, Avery certainly has her hands full. She does her best to keep her distance and avoid any association between herself and her family in the minds of others. While she doesn't quite go so far as to lie, and even half-suspects most of Slytherin has figured it out by now, so long as they don't ask, she isn't about to volunteer the truth.
Before starting at Hogwarts, Avery was by and large an introvert, a loner. Her family didn't understand her, nor did she want for them to, and she had no friends. As such, being so welcomed in her first year, she revels in the attention of the older students and works hard for their praise, if she deems them worthy.
Avery works hard at school. She does her homework, pays attention in class, and is always prepared to learn more than is necessary. But it isn't because of a love of learning. No, Avery is only interested in those things she can use to 'get ahead'. Spells, potions, even simple knowledge - she sees that they can all benefit her in some way. She's on the path to becoming the most awesome witch of all time, after all.