I'm not saying they were children and I'm not saying they were incapable.
Those thing exist, those are easily learned.
I'm speaking on the concept of death.
Death came into the world due to sin. Before that, death doesn't exist.
How can Adam truly grasp the concept of death when it doesn't exist?
I compare it to the child not knowing what hot is, and that child testing the waters to learn what hot is. Not to the child itself, but to the idea of not fully understanding a consequence.
Eve told the serpent "but I was told.." and didn't show she actually understood consequences, again, those don't even exist here.
The serpent didn't actually lie, per say. He was very sly in his wording. Careful to persuade them.
The fact they were ashamed and hid also shows they didn't know or understand what would happen. They knew they fucked up immediately after because now, biblically speaking, good/evil, right/wrong have truly entered the world. Meaning, beforehand, it didn't exist and they knew nothing about it. Which is exactly why it's called the "tree of knowledge".
So there's a contridiction. They did something they did not know what actually wrong; that would have actual consequence to their lives (and the lives after theirs).
They were manipulated by God through lies (withholding information).
At the end of the day, though, regardless, this is all God's grand plan; his will. So if his will shall be done, then how does none of this make God the bad guy? He purposely manipulated the situation, as he did with many others in the bible (the pharaoh is a huge one), for his own selfish reasons.
It's almost like when God and the devil faced off in heaven, the devil actually won, taking God's spot, then banished God to "hell" and God is just simply the devil, which is why the devil (God) is trying to get people to not listen.
^would make for the greatest plot twist in history..