hi clay,
stop thinking about your dream girl being a jehovah's witness and start thinking about her as being a member of a destructive high control group. Don't worry about the specific beliefs of Jehovah's Witnesses, don't worry about 1914, Rutherford,holidays and other JW details. Instead focus on the psychology behind what has linked her to this high-control group. Is it family and friends, is she attracted to the dogma, does she ned to have a controlling factor in her life?
What will she experience if she leaves her high-control group? Rejection? Isolation? Is she prone to depression? Is she manic? Co-dependent? What are her personality traits?
If she left, how would she put food on the table? Would she go to college? Where would she live? With you? At twenty years old, that's a tall order for you both.
Looking at it from her perspective, what are the benefits of her leaving (not the benefits for you, but the benefits for her)? For her perspective, what are the benefits of staying? Does she want to leave?
Write these things down so that you can make a better assessment of some of the factors that are contributing to her decision making process.
Then go to the library or the bookstore and look up steven hasan's books. He's an expert on cults. It's a must read if you are seriously considering attempting to get her to leave a cult.
it might be helpful to look at other books on sociology/psychology and cults.
Just some thoughts.