Idk if anyone knows her backstory too well but basically Nina's entire life was planned for her, she was going to be a model like her mother and be married off to some rich dude more than half her age older then her(and she takes physical and emotional abuse from her parents which the added bonus of having to hide that from her little brother for his own good). Which is why she's so depressed all the time(though she escapes this fate eventually.)

(Bonus ponytail pic)