Cult members are in a constant state of conflict as the beliefs taught mess with their heads. Most on this board are ex-JWs and have first hand experience which is why it would be smart for you to pay attention to the advice provided even as it is not what you want to hear.
This girl maybe able to give in to her desire to have you as a boyfriend now, but the religion's teachings will at some point overwhelm her and will create much confusion, family conflict and guilt and so will create drama in your relationship. Major life events (marriage, birth of a child, loss of a loved one) and world disasters will often be a trigger to more closely follow the teachings, often in an obsessive manner. She will push for you to become a JW in an attempt to make things right with Jehovah.
While you may think you can eventually get her to leave the religion, unless leaving is fully her idea, there is high likelihood that the teachings will always remain with her and she will return to it, with or without you.