The church-age began at Pentecost (Acts 2:1-47) and ends with the revelation that the church has been translated (1 Thessalonians 4:13-18), called the Rapture. Immediately after the rapture of believers, the Tribulation (Matthew chapter 24:4-14) will begin and last seven years.
The Rapture is distinguished in Scripture from the Second Coming of Christ, which culminates the Tribulation period (Matthew 24:29-31).