Adam and Eve not obey God, so they die. Genesis 3:6, 23
Eve listen to the snake and eat from the tree. Then later on, she gave some to her husband then he eat it too.
The thing they do was bad—and da sin. So God put them outside from the Paradise home.
Life was not easy for them and their children. They start getting old small-small until they die. Nothing move from in them to go live anywhere. When they die, they die.
When we die, we just like dust. Genesis 3:19
Jehovah not make human being to die. So very soon, he will bring those sleeping in death back to life. If they listen to God, they will live for long time with no end.