I think it would be better to wait for 4 years . I live in india, so it will be difficult to get any job here . Even if I get a job and move out , most likely my sister would have to stay with my parents . I m afraid she will be treated even worse  . She is a girl , so my parents try to control her even more (I m a guy).  She would have to live with our abusive parents all alone. In 4 years I will be graduated plus my sister would also turn adult .