I’ve seen your situation several times over the years. JW girl meets nice non-JW boy. Elders find out. Girl is told “Remember, Jehovah wants us to marry only someone in the Truth™. Let’s see if this guy is really a good, sincere future JW. Keep your distance until he’s studied and gets baptized. So that way you will know he is getting baptised for Jehovah, not to get married to you. Then you are free to marry him”.
JW girl follows the rules and distances herself (at least in front of fellow believers). Boy really likes this girl and believes he can change (help) her. He too follows the JW rules. He studies. He gets baptized. Sometime after his baptism they get married, blessed because they followed the congregational rules.
Then….the marriage becomes a total disaster. The guy was interested in the girl, not the religion. The girl wants to keep the religion and the boy. There’s a lot of finger pointing and fighting. All the JW congregation nod knowingly and say to one another “See, a “worldly” guy. Can’t be trusted. He came into the Truth just to marry her” and “She went out into the world™ just to get a guy and look what happened. She should have known better. She disrespected Jehovah’s rules”.
Want grief - get baptized. Want to clear everything up? Tell her you have done a lot of research and have positive proof she is in a mind-controlling cult and you will NEVER join - NEVER. Show the elders and your GF the proof. See where it goes from there.