Mary totally accepted this without question. She had to have had doubts in the back of her head, but answered instead with the faith of her heart. Man, if only we could accept the will of the Lord in the same manner in our lives!
As far as informed consent....how differently would things have gone if she had answered, "Wait a minute! No one asked me!!" She is a great example of faith for us because she didn't answer this way. We often don't respond in the same way of consent though. We ask for explanations, we give God suggestions, we do everything BUT what Mary did!