My mother is a doctor and does not want me to take finasteride although I want to

You have to deal with your mother and possibly bring her to a consultation with a doctor who has experience with this drug to discuss the difference of opinion between yourself and your mother. If I were your doctor, I would encourage her to join us in a consultation. Maybe she knows more about you that is relevant to her concern, maybe she does not understand the real risks. Only a one=on-one meeting between your doctor and your mother with you present, is the way to manage this problem.