COG Ahnsahnghong ] Why were we born on Earth?

The Bible says:

Rom 3:10-12 "As it is written: "There is no one righteous, not even one; there is no one who understands, no one who seeks God. All have turned away, they have together become worthless; there is no one who does good, not even one."

Luke 5:31-32 "Jesus answered them, "It is not the healthy who need a doctor, but the sick. I have not come to call the righteous, but sinners to repentance."

If all of us are sinners, when and where did we sin?
The Bible says:

Ezek 28:12-16 "Son of man, take up a lament concerning the king of Tyre and say to him: 'This is what the Sovereign LORD says: "'You were the model of perfection, full of wisdom and perfect in beauty. You were in Eden, the garden of God; every precious stone adorned you: ruby, topaz and emerald, chrysolite, onyx and jasper, sapphire, turquoise and beryl. Your settings and mountings were made of gold; on the day you were created they were prepared. You were anointed as a guardian cherub, for so I ordained you. You were on the holy mount of God; you walked among the fiery stones. You were blameless in your ways from the day you were created till wickedness was found in you. Through your widespread trade you were filled with violence, and you sinned. So I drove you in disgrace from the mount of God, and I expelled you, O guardian cherub, from among the fiery stones."

And the Bible says that the devil and his angels were hurled to the earth.

Rev 12:7-9 "And there was war in heaven. Michael and his angels fought against the dragon, and the dragon and his angels fought back. But he was not strong enough, and they lost their place in heaven. The great dragon was hurled down--that ancient serpent called the devil, or Satan, who leads the whole world astray. He was hurled to the earth, and his angels with him."

Through the above verses, we can see that all men are sinners expelled from heaven.

Then is there no way to returning to our heavenly country?