Who is Agatha Pinney from --and Ladies of the Club and what is their importance?

Never married, Agatha Pinney is described as a "thin, ingratiating little spinster". Agatha is a primary school teacher and one of the initial founders of the club. Over the course of the novel, Agatha finds herself addicted to opium, which was prescribed as pain medication to treat sciatica. Her addiction becomes a huge problem for the members of the club because they believe she is no longer able to teach their children. When she is forced to retire, Agatha is unable to generate enough money to soothe her habit. She later takes her own life.