God is always fair, so he does not require more of anyone than they can do. He created the first man and woman perfect. There was no inherited sin in their makeup. They did not get sick.
They also did not have to deal with the pressures of a wicked society. The work that they had to do was pleasant, but it kept them busy, and they were encouraged to learn about their environment by naming the animals.
They didn't even have to ask themselves whether or not God existed, because their Creator spoke directly to them, and they knew that their beautiful Paradise came from him.
The first and only issue for them to decide is whether or not to obey God's command regarding the fruit from one tree.
They wouldn't starve if they obeyed him, they were surrounded by food. More than likely they knew what death was because they were able to observe the animals, who were not created to live forever. The question that they had to decide is if their Creator, who loved them and provided for them had the authority to require that they be obedient to him.
A creature, who never did anything for Eve, and who hid his identity behind a serpent, lied to Eve, saying that she would not die, and she believed him over her Creator, and apparently over her husband as well, because Adam had added the command that she was not to even touch the fruit. But when confronted with the knowledge that his wife ate it, Adam, who knew that she was being lied to, preferred to go along with her rather than obey his Creator.
" Also, Adam was not deceived, but the woman was thoroughly deceived and came to be in transgression." 1 Timothy 2:14
We could say, if we did something that we did not mean to do, that it was a mistake. But they were perfect, "very good" Genesis 1:31 Their choice, although for different reasons, was deliberate. They condemned themselves, and us, to a cursed life that ends in death
19 In the sweat of your face you will eat bread until you return to the ground, for out of it you were taken. For dust you are and to dust you will return.”
12 That is why, just as through one man sin entered into the world and death through sin, and so death spread to all men because they had all sinned—.
However, Jesus, through the ransom paid through his death, provided the opportunity for deliverance from death for us.
23 For the wages sin pays is death, but the gift God gives is everlasting life by Christ Jesus our Lord.