In my experience, as a former member for thirty years, the long term outlook is not good. Being in a religion like this, her thoughts and emotions have been manipulated. She may be in love with you, but eventually the guilt over the relationship will get to her. If she does stay with you, her religion will be a factor in your relationship.
If you get married, she will feel obligated to raise your children in the religion. They discourage higher education, have strict requirements for attendance and door to door work. They do not allow blood transfusions, voting, holidays or association with non believers. They believe they are the only true religion, all other people will he destroyed at Armageddon, which will he soon.
I get that you love her and you think you can make this work out, but you should know what you are up againet. It's a cult, and they also are highly critical of other Christian religions, especially Catholicism.