Every person is different. Many swear they'll never go door to door - but they eventually do.
If your wife has spoken negatively about the witnesses to her friends then she'll have to get over her embarrassment before she lets them in on the latest news.
She may not be discussing it with you because you are going to try and reason her out of it or she may also be embarrassed and not want think about you looking down on her intelligence for studying, especially after the negative talk (not that you do look down on her - it's an irrational fear - everyone has irrational fears).
I would say that when she does start openly mentioning it and telling others - she's bought it hook line and sinker. You have until just before she starts telling others to get her out. First comes her internal decision of acceptance and then after an unknowable period of time comes her verbal affirmation of her internal decision.