The choice I make will be eventually be predetermined by the evolving process of deciding which choice to make.
And by every other possible influence. Although I do disagree with "pre-determined"... as this does not allow for randomness in outcomes. But I'll put that aside for now.
So the choice will be predetermined yet at what stage do I not have the freedom to reject all or any of that predetermination?
You never have the freedom to reject it. By thinking you reject the predetermination you are merely following the same pre-determination.
E.g. you may think that pre-determination was going to lead you to pick A. And then you change your mind and pick B, believing you have rejected the predetermination.
But you haven't.
The pre-determined course of events had you picking A, and then changing to B.
How can one say I am not free to choose between all three options AT ANY TIME or change my mind even after deciding prior to actually acting on the decision made.
We all have ability to "choose". It is just how you define / understand "choice" as to whether you consider it illusory or not. Mirages exist, but they are illusions of what they might appear to be.
So at the point of actually acting on that freedom to choose [time=0] I am totally free to choose between the three options.
It depends on how you view/define "free-will". If you define it as the pattern of activity that gives the appearance of self-determination then yes, you have "free-will" - your choosing is such a pattern.
But the pattern itself - the movement and interaction of the fundamental molecules etc - has no self-determination - and thus the illusory nature.
Once t=0 occurs the choice is made and acted on.
So unless you can show how I have somehow lost my freedom to choose prior to t=0 then self determined freewill is evident.
You can not lose what you never had
At t=0 the "choice" is made, but that "choice" is fully caused by the moment t=-1. The atoms / molecules / quarks etc that made up t=-1, together with any spontaneously / randomly created particles/energy, are the only influences for t=0.
Those influences at t=-1 are the cause for t=0.
The output at t=0 is fully driven (if not strictly determined) by that cause.
At no point between t=-1 and t=0 is there the opportunity for a "choice" at the microscopic level.
All we end up with is the macro-level pattern of activity that gives the appearance of "choice". Hence some say that this ability to "chose", this "free-will", is illusory - as it does not actually exist.
Similarly one says that a mirage is an illusion.
The mirage exists (as a pattern of activity that gives the optical appearance of, say, water) but what the mirage depicts is the illusion - e.g. the water is illusory.