Signing up is easy. Still being there in week six is the real decision.

Joining costs a form and a moment of enthusiasm, neither of which requires much of you. The commitment is made later, on the evening in week six when it has become ordinary and nobody would notice your absence. That is the point where most groups shrink by half. It is also where everything worthwhile about being in one starts.

Plan for week six now, while it is still easy. Tell someone you are going, put it somewhere fixed in the week, and expect the flat patch instead of treating it as a sign. Staying through it is the whole skill.