Again you are assuming that there are elements that will have prepared you to make the decision.
I posit a situation where there is a situation where there is nothing to prepare you as the situation is entirely novel and unique.
I'm just assuming that there is a person, complete with a personality and state of mind, and how that person reacts to anything at all (even if it's entirely new) is determined by those things. It's
totally irrelevant whether anything it that person's past has
specifically prepared them for what they encounter or not.
I am not though precluding a faculty for recognising that which one is experiencing just that nothing external determines a single response.
The distinction between external and internal is also irrelevant because we are considering both. The internal (the mind of the person) either got to be the way it is deterministically, via all its nature, nurture, and experience, or, since there is nothing else that could affect it, with some random element.
Practically, because of the uniqueness of a situation it is impossible to turn back time as you suggest doing .
Of course it's impossible in practice, that's why it's a
thought experiment. They are very useful at uncovering the
logic of a situation and the fact that you won't engage with it (just like Alan) speaks volumes.