I am sorry to hear about your daughter.
Usually three elders meet with her to discuss what she has learned from the Bible Watchtower. There are a set of questions (I forgot how many) they ask of her. It's pure formality, not a test, if she knows the basic ones (and you can be sure she knows the most basic, probably even you know that much) she "passes". Of course the elders also judge if her life is according to the Bible Watchtower principles (she's not excessive drinker, gambler, she left her previous church, she's not fornicating, not smoking, not celebrating Christmas/birthday/Valentine's day etc.).
After this, usually on a convention, there is a special speech to the baptism candidates, at the end of which they are asked two questions:
On the basis of the sacrifice of Jesus Christ, have you repented of your sins and dedicated yourself to Jehovah to do his will?
Do you understand that your dedication and baptism identify you as one of Jehovah's Witnesses in association with God's spirit-directed organization?
They must answer Yes to both of these questions, after which they are taken to a pool and submerged fully in water. After that their personal data is collected (address, age and such), and they are fully members of the cult.
Edit: normally, preceding everything above there should be a "dedication of yourself to Jehovah", that is technically a prayer, but because it's not often discussed in detail what they should do/say, and it's a private thing, many people actually forget this step (I know I did and I think I've seen a thread here where others said they didn't do it either).
About the Blood Card: she is very likely to already have one. It's given once it's requested, but I am sure the lack of it would be a serious barrier to her baptism. I am not sure of its legality, especially in regards to UK law.
