How long have your parents been divorced? Does your father have full custody and your mother just visitation rights? At age 15 the courts should listen to your wishes.
Children need both parents but unfortunately that is not always the case. I do believe when a mother is able and a fit mother she should have the children most of the time. She is the nuturing one and especially with a daughter, there are things only she can explain to her. A father would just not know where to begin. If you want it, with your moms help you will accomplish it.