I accepted it from pastors I heard teaching it when I was a young believer.
Then about 15 years ago, I started testing all the teachings I'd been subjected to, to Scripture itself.
The more I read, the more I became convinced that Matthew 24 and Mark 13 is the timeline for all things "rapture-related".
The church will be here through the 3.5 years, and will suffer many losses as Satan is given the power to make war with the saints and to overcome them...believers will be put to death for not taking the mark.
Then at the last trump, when first, the dead in Christ shall rise, we which are alive and remain shall meet the Lord in the air.