If it's difficult to talk to them about this subject, write them a heart-felt letter explaining that your dating at 17 is really not their decision to make. Tell them that you are going to be as responsible in the dating area as you have been in all the other areas of your life. You have learned good values from them. You may make some mistakes but how else can you learn unless you make mistakes along the way. State that they should show you the respect and trust that you have earned and that you are not going to stay away from dating merely because they forbid it.
I understand that you, and certainly they, may think that I am encouraging you to defy your parent's wishes and authority. What I am doing is encouraging you to break away from the overprotective, unfair rule of your parents and to allow yourself to mature socially. You are ready and unless I am missing a vital piece of information you should be allowed the freedom and responsibility to date. Perhaps there are trusted family members or friends of the family who will show their support for you in a non-threatening, non-judgmental way. These decisions take courage but they are part of being an independent young woman. Thanks for writing.