Could a JW explain how sin came about, and how sins are FORGIVEN?

Adam was a perfect son of God. God's first human creation. He sinned and by doing so he lost the ability to live forever on the paradise earth. He ped that sin on to all humans so nobody could live forever. People would die and that would be the end of them. God knew that those people who would be born to Adam and all generations had no say in the matter. It was not our fault that Adam made a bad choice. A sacrifice had to be made for Adam's sin so that we would all be able to live forever on the paradise earth as God intended us to. The sacrifice had to be equal to the sin. Who was perfect like Adam? Who would be an equal sacrifice for him? Nobody. Jesus who was God's first heavenly creation offered to come to earth and be born as a human so that there would be an equal sacrifice to atone for Adam's sin. Jesus was born perfect and he showed by his life that humans can live up to God's standards. When Jesus died his death bought back our eternal life. He died for our inherited sin from Adam. Now all people have the possibility of living forever on the paradise earth again. Soon God will take back rule of the earth from Satan and restore it to the original paradise conditions. All who survive Armageddon and all those resurrected from the graves will be able to live forever if they want to. Christ died for our inherited sins only. Not the ones we commit on our own.