OMG - I feel sorry for you! JW's are a CULT not a religion. You have no idea what a huge impact this will have on your life. You will never celebrate Christmas in your home again. If you want to spend Christmas with your family be prepared to go alone and to fight about whether the kids can go with you. My dad was not a JW but I never got any christmas, birthday, haloween, easter, etc. - not because he believed it was wrong - but because of the constant bitching preaching from my mom.
The blood issue is life threatening -- do not discount what a JW will do in these situations.
Please, please, please do a lot more research about this destructive cult before you marry into it. Some suggestions: Crisis of Conscience - Raymond Franz, Releasing the Bonds or Combatting Mind Control - Steven Hassan.
Don't think that you will be able to "fake" your joining and just quietly maintain your own beliefs and your own life. The pressure will never end to be a better witness - go in more service, pioneer, etc, etc, etc. You will have to agree with every false prophesy and piece of garbage that the WTBTS puts out or else you will be DISFELLOWSHIPED and then the nightmare will really begin!
I know the thought of ending a relationship over religion probably seems a distant and unwarranted option. But this is not about incompatability over religion - like it would be if a catholic were marrying a jew. That would bring with it some issues. But you would be marrying a cult member and that brings with it a great deal of baggage. If you doubt that it is a cult - just mention the word to her and watch what happens. You will be discounted and she will probably bring up some other cult - like the Branch Dividians to discredit you. But she will not encouraged you to discuss further the idea of the JW's being a cult - nor will she read Hassan's book.
In summary: RUN