Welcome To YT!
The breeder could have had a bad experience with people trying to take advantage of her and puppies. She migght be on the overly cautious side of things. However, you have every right to ask as many questions as possible, and get honest answers . I would not put money up front then, until you have the puppy and is ready to go to you.
You will also need to use caution and protect yourself from any scams, or puppy mills. Just use your judgement, and if it does not feel right then do not do it. Find anther breeder that is willing to work better with you.