I really like the backstory of your sim, it's very well thought out and I just love it when players invest so much time in creating them!
For me, I have many different sims I like, but I guess I just pick my current favorite (this might change later).
https://www2.pic-upload.de/img/35106621/02.04.18_13-27-20.png
This is Alyssa Eddison, and I originally created her as a friend of one sim of my main family. I didn't even plan to actively play her, but now I do it often because I just like her overall style (she's a pure tomboy and I just love that!) She is a geek, a kleptomaniac and cheerful. She has the City Native Aspiration I am going to complete on her soon.
Her story? Well, she comes from a supposedly "perfect" family. However, things weren't as perfect as everyone believed. Her father cheated on her mother in front of her and her brother, but her mother wouldn't listen to her. Her brother started becoming more and more rebellious and always brought the family into trouble, causing even more stress for their mother. However, Alyssa was still very popular in school, because she was friends with the ultimate party girl, Regan Lemons, who is her roommate today:
https://www2.pic-upload.de/img/35106620/03.04.18_09-46-47.png
Her roommate Regan is a serial romantic who is going to have 3 relationships at one time. Alyssa is feeling bad for these guys, especially because Regan is just playing with them and will leave them behind anyway. It reminds her too much of her parents because her father only married her mother because she had a rather wealthy family. Fun fact: In an older save, Alyssa had a secret relationship with Arun Bheeda, so she is a homewrecker herself, but would never admit it. I think I will go this route again and see what's happening if Jesminder finally finds out :D
I will bookmark this thread, it's always interesting to see some stories :)