Not to put a too sharp a point on it, but in the minds of the Witnesses, YOU are a "worldly person", i.e., an undesirable in their world if you don't convert to JW.
On the other hand, the girl you are "dating" would not be considered a "strong" Witness if she is dating, a) at all at a young age, b) dating a "worldly" person.
Good that are you are thinking things through. We might have good intentions giving you advice, but we are strangers.
So, my advice to you comes from TWO poinnts of view: I am the father of a 14 year,old son AND I am a former elder in the Witnesses and left the cult. MY ADVICE ...kindly, gently, stop dating her. You are too young, and the cult is dangerous. Be friendly, but put some distance emotionally between you. Cool down.
If in a few years she leaves the cult ON HER OWN NOT FOR YOU and you reconnect later in life, that would be great...but don't hold your breath.
I wish you well young man.