Book clubs are brutal for this exact reason. One person who actually read the book closely can wreck your whole track record in about ten seconds. My advice is to pick the movie version ahead of time and just say you're comparing the two, gives you an out. Also keep a couple of safe bets in your pocket, like anything with an unreliable narrator, so you never have to guess cold. Eight years is a good run though, don't let Denver take that from you.