Here is a link to Steve Williams book What is Christianity. Steve used to preach at University City Church of Christ in Gainesville, FL and teaches at Amridge University (formerly Southern Christian). It is currently out of print but has been provided to download/print. It is an excellent resources that highlights our core beliefs in 30 pages. I would encourage you to pass this on to people of all maturity levels as well as people who are asking questions about Christianity. Here is the link. Never hurts to be free!
For many years, my in-ness or out-ness varied moment by moment…even second by second based on how well I performed