Why do I get the stink eye from a Bible study group?

When I went to a church last fall for a turkey dinner, I noticed on their bulletin board that they were offering a Bible study. Since I am now retired, I was looking for something to do besides watch TV and surf the Internet. So I asked the pastor if the study was for church members only, or could anyone come. She said anyone was welcome. They meet one morning a week and I've been going to it since last November. We read a chapter, the discuss it with the pastor's guidance. I am familiar with the Bible, having read it through 5 times. If there a question at the study, I usually give the others that attend a chance to answer (the other attendees are senior woman), but more often than not, they just sit there and look uneasy, so then I chime in. Sometimes the pastor is so impressed with my answers that she writes them down what I say to use in her sermons, commenting that I am inspired (or something to that effect). However, when that happens, the other study members usually give me sidelong annoyed glances when I speak and especially if it impresses the pastor. Why should what I say bother them so?