She will feel happy for a month or two. Then, when she gets used to you, she will miss her family that will not speak to her. She will miss her whole tight circle of JW friends. They will not speak to her or acknowledge her. They consider this a loving arrangement. Depression will set in, and she will eventually blame you for everything, even though you may not be the cause. If you go into this, prepare for horrible events to come your way. So sorry to tell you this, but it always happens. If you end up marrying her, I advise you enroll in psychology classes to keep you sane and knowledgable on who you really are. Prepare for psychological sessions with a professional for both of you. If she is mentally strong, then she should be able to forget her family and the circle of friends she has been culturing all her life, this will take years, many years. You will need grand patience if you sentence yourself to years of personal grief, and negative emotional stress. Pray to whoever you believe in, that she does not become suicidal. My opinion? Do not get dragged into this, and just keep her as a friend, or girlfriend that lives separately from you. Give her support and treat her like a human being, even during the times that she grows to loath you for taking her family, and friends. People always tend to place fault on others, when they ruin themselves, and if she stays in the JW disorganization, then she will grow to blame you and consider you the filth of the earth, in her eyes, you will die in Armagedon. They are right, this is a Cult! Value yourself for the good person that you are and don't adopt problems.
So sorry and welcome