nah its more like since she's a noble she needs to listen to her father because he obviously has an higher authority than her and wants to use her for his goals disregarding her opinion. although she is still quite impulsive and I don't really like her, her father being a piece of shit isn't her fault
I know some real world historical info about gender roles so let me explain a bit.
In the kind of setting this story has, daughters are married off to families that can help their own family to have more wealth/honour/reputation/power. These marriage partners are always chosen by the parents, specially the father. Maybe they wanted her to fall in love with some noble she meets and marry that person but since she is that old, the father decided her partner without caring about her because it's already time for her to get married (Historically, 14/15/16 yo girls were already at least engaged or married).
Female nobles have only one job and that is to get married to another family and produce heirs. Sometimes, they will be allowed to have some kind of power within the household (mostly finances) acting as their husband's substitute. Female commoners (specially farmers and such) could work while taking care of the children because the family needed all hands on deck helping. So, as a noble, she will never have to work a job in her life.
Furthermore, she cannot be the heir. Only males can be the heir (unless the author changed this for the story) but even if she doesn't inherit anything, some male family member will and will have to take care of her if she's not married if the Duke puts that condition in his will. However, it isn't common because mysoginy and the belief that women should be either nuns or married.
Hope this helps, I studied this some years ago so maybe there are some mistakes.
If someone is curious, there is a text called Liber Manualis written by a woman (Dhuoda) of the 9th Century for her first born that shows the education of woman of that time.
I find the other girl odd. She's already an adult but parents are still the one to decide her marriage for her? Does she not have a job? No plans of marriage and still want to continue to live under her parents? Is she the supposed heir?
Can someone give me a little bit of her background? Is she an impulsive character?