Mrs. Luce, the editors wife, is introduced in The Meek Shall Inherit. During all the commotion around Seymour as he springs to popularity, Mrs. Luce offers him a contract to be on a very popular, exclusive magazine.
She is a very flirty character, and as we are not told her age, we can assume that she is quite young as she is bubbly, flirtatious and very eloquent.