Most people were never taught about the three earth ages.
The First Earth Age:
God created this earth, billions of years ago. (Gen. 1:1) He also created about 12 billions of us in our spiritual body; Dinosaurs were also created at that time. (Job 40:15-18.) Satan (Ezek. 28:3-19) deceived one third of us to follow him in that earth age. (Rev. 12:4) God did not want to destroy that one third along with Satan at that time, so he took all of us up to heaven, then he destroyed that earth age by shaking the earth. The earth was shake off it axes (That’s why we have the Grand Canon) and all the Dinosaurs along with other creatures were destroyed.
The Second Earth Age:
After the earth had settled from that massive shaking God created man and woman, (Gen. 1:26-28) so that each of us could be born through a woman and choose who we would follow, God or Satan. In this earth age, God sent Jesus to save us from Satan. Those who choose follow Jesus will have everlasting life and those who choose to follow Satan will not live in the third earth age. We all are now living in the second earth age. This earth age is about 6,000 years old.
The Third Earth Age:
When Jesus returns, that will be the beginning of the third earth age, (Rev. 19:11-16; 19-21) Satan will be cast into the bottomless pit for one thousand years (Rev. 20:1-6) Satan will be released for a short time then he and all his followers will be cast into the lake of fire. (Rev. 20:7-15) The new Jerusalem and God will come down on earth, Rev. 21:1-21) and we will live on into the Eternity. (Rev. 22:1-21)
For more detail of the three earth ages please visit the following website: