> Yet, if I simulated every molecule of my body

This gets into the concept of free will.

If you have free will, then it is your own conscious decisions that are affecting the universe, and not the universe affecting your conscious decisions.

In this scenario, you can't "simulate every molecule" of your body, because that simulation will have to include whether or not you decided to touch that hot stove. And that decision rested solely with you, in your mind.

If we do not have free will, and this whole thing is "on rails", then we are essentially watching an elaborate movie play out that we have no control over.