Telling your daughter you want her to be free to be herself would probably be the single greatest thing you can do. Let her know whatever decisions she makes for her life you will support. I find it highly hypocritical that Jehovah's Witnesses sing a song about "Make the Truth you own" and yet they demand that the religion be imposed on their children.
If your daughter wants to be one of Jehovah's Witnesses let her know you would support her decision. Let her know it would make you feel better if she made that decision after:
- She thoroughly examined the history and teachings of the Watchtower
- She is familiar with the practice of Disfellowshipping based on the Watchtower's own articles
- She makes the decision as an informed adult
- She makes the decision because that is what she wants and not because it would make her mother happy or our of fear from being kicked out of her mother's house.
In other words, she really does make it her own.