The bigger the guild the better. A small guild there are not many to take charge of different projects and activities. My experience in a small guild, the new members get overwhelmed with requests to take an office or be on a committee.
When you go for the first time, don't sit in back and wait for members to come to you. Take a show and tell and when it's your turn, announce your name and tell a little about your quilting experience and what you would like to learn from others. If you encounter an old biddy or two, just smile and think I'm sure glad I'm not her.