Ah yes, been there, done that. I have my own thread on this particular topic, because I'm in a relationship with a JW, too, though my situation is a little different. My boyfriend is an unbaptized, inactive JW who never goes to KH, his whole family has known about me all along and they all like me very much.
But the bottom line here is, as long as the JW in a JW/non-JW relationship remains a JW, then there will always be tension in the relationship. The non-JW will never be a priority in the JW's life unless he/she converts, and even then, Jehovah, the congregation and things like field service will be more important than the relationship.
Just like everyone here who posted on my thread told me, I'm gonna tell you that it's probably not gonna work out and that your best bet is to get out while you still can. I'm assuming that you're young, do you really want to have to deal with the WTS for the rest of your life?? Because if you stay with this girl and she stays a devoted JW, then that's how it's gonna be. The WTS controls every aspect of a JW's life, even personal matters like sex, and if you stay in this relationship with a JW, then the WTS will control her life and therefore your life with her.
If you want to pursue this relationship, just like I continue to pursue my relationship even though it appears to be quite hopeless, get the facts. Do the research, learn whatever you can, get all of the advice you can from those around you. This board is good for research and advice, most of the people here have first-hand experiences with the WTS, either as JWs or as people connected with JWs, and they definitely know what they're talking about. Don't shy away from learning the truth about the WTS and its doctrines and teachings. You have a right to know what you're getting yourself into, don't let anyone discourage you from researching.
Just remember that a relationship with a JW can be very heartbreaking. I've been seeing my boyfriend for almost 8 months, and celebrating Christmas without him was heartbreaking for me, especially after the mean comments he made about Christmas even though he knows it's my favourite time of the year. JWs are desensitized to the feelings of non-JWs, they say things and don't care if they hurt someone. They don't think there's anything wrong with belittling a non-JW's religion, beliefs, practices or celebrations, but they will claim that they're being persecuted if anyone says anything against their beliefs (yes, that hypocritical, but so is most everything that JWs practice and believe). And they will refuse to participate with you - if you like things like Christmas and birthdays, don't get your heart set on sharing these things with her, because she thinks they're evil and she won't hesitate to tell you that.
She looks down on everything you believe and do whether she actually says so or not, remember that.
Good luck, and stick around the board, these people know what they're talking about!! If you want to ask me anything, send me a PM.