first of all, if she's just starting, you need to pound your friend with information. Because at first before you are actually "in" you are flooded with friendliness and fake smiles and such. They beat around the bush for awhile, but then it sinks in that you's not gonna get out.
Problems = religion. They take the bible for themselves, so if you are not a JW, you are not "in the Lord". They refer to this statement i think as being a Jehovahs Witness, but i believe this statement of "in the Lord" as being a follower of Lord Jesus.
It will become the 3 of them...Man, Woman, and the Elders. They'll tell you that the 3rd is God, but its just the elders making decisions for you guys
Unless you guys sneak around you'll never be alone. NEVER EVER EVER. its a bad no-no to be alone when you are a dating couple as a JW
Eventually if your friends decide to get married the JW will get ridiculed and "marked" and such because she has an "unbeliving" husband. It starts to happen when you have an ubeliving boyfriend/girlfriend, but it really sets in when the relationship is deep.
The non-believer is going to start hearing rubbish about the End and Jesus returning in 1914 and such, and thats going to be all she'll talk about because thats what they "program" her to talk. If you aren't out in service you need to be indirectly witnessing.
If you want more info, like i said, get ahold of me thru email ^^.