Hey Stephanie,
This is just a suggestion:
Ask her to study one night from just the bible, no WT literature. Tell her you have thought about a lot of the things you have been learning and done bible reading on your own. Ask her to read the bible book of Galatians with you. Try to have a version of the bible handy, like a Living Bible, for your study, don't let her bully you into reading her version only. By the way, the WT version says the same thing, its just harder to understand Paul's true meaning of Christian freedom with the WT version.
The book is only 6 chapters long, not to much to handle in one evening. After reading this with her tell her you don't understand the difference between Paul's view on circumcision and the WT view of celebrating holidays, the ban on blood transfusions, being disfellowshipped for smoking, etc.
This is not a trick to stumble your friend, its a bible based view of how true Christians are not to be tied to laws of man.
Now I'll warn you, this is not an end all for your discussion with this witness. I've studied these exact scriptures with my wife and she still thinks of the WT as Gods organization. This is only a starting point for you and perhaps your friend, into Christian freedom.