Jonza, I have no doubt that you love this woman, and you have the final choice here, but you are already getting a glimpse of the future. You are only seeing a glimmer of the cult personality. The fact that she has a relationship with you, a "worldly man", convinces me that she feels she can change you once you are married. She has convinced herself that whatever she is doing now will be forgiven after she repents and brings you, a living offering, to the altar of the WT. This is a very tough situation...I would confront it head on. Tell her you will NEVER become a JW, and forbid any children to be raised as JW's...see what her reaction is. I am guessing she will say it is ok, but you will notice "tells" in her body language to the contrary.
Remember the old adage..."Men marry women hoping they will never change, and women marry men hoping they WILL change!"