Dating the Return is one sure sign there is a fatal flaw somewhere in the theology however good the rest may sound....
Look, if you want to ignore the fact that the stars and planets align as it is written in Revelation 12:1-2 on September 23-24, 2017, be my guest. If you have confessed with your mouth that Jesus Christ is LORD, and believe in your heart that God raised Him from the dead, then you will be saved. That means that you, probably, get to go on the first harvest whether you believe in it or not.