Its not something to be kept as a secret. It is giving scars to both body and soul. How could a father do this to her daughter. I can understand, when its about family, we think a thousand time to take any step. See, your mother could be saying so because father is the bread and butter earner so she must be thinking of finances. It is something unbearable and should not be tolerated at all. So, try to solve it with help of some one from your family such as some elders you could trust. If at last no option, report it, because no one could touch a female without here permission, its a crime.