14 Year Old Girl Seeking Legal Advice Regarding Parental Custody?

Hi, I am a fourteen year old girl living in Oregon, and a few months ago my parents told me that they were getting a divorce. My mother is emotionally abusive and unstable and constantly cries whenever I tell her that I do not wish to spend my time with her. She has, in the past, been in a physically abusive relationship, where she gave birth to two sons, my half-brothers. Then, she met my father, who is sweet, caring, kind, and is a member of a charity that ists victims of domestic violence. A few years later, they had me and my younger sister who is nine. My mother has always favored my younger sister because she is very impressionable and does whatever my mother says. My mother only eats one meal a day, if that. She is anorexic and is constantly putting herself down about her weight, which sets an unhealthy example for myself and my younger sister. She makes herself seem like the victim who can do no wrong in every situation. She is always right in her eyes. I am seeking legal advice because I do not wish to live with her any further. I have expressed this to my father, who has discussed it with his lawyer. My father is very vague regarding the divorce, and when he spoke to his attorney, he said something along the lines of 'the judge will decide what is best.' This upset me a little, and so did my father's statement where he said "I think it's healthy for a child to have both parents in their life". I confronted him (my brother's advice) about this, and asked him if he even wanted me to live with him at all, because it really didn't sound like it. He told me that of course he wanted me to live with him, and that he wished he could have me and my sister live with him all the time, but it was ultimately the judge's decision what is best for the child. My father is being unhelpful, and my mother has not found out yet about me not wanting to live with her. I really need someone's help. I don't want to have to be stuck living with an unfit, unstable parent, and I especially don't want my sister to live with one. Please help me.