My theory. God created time and space. He's in it and not in it. He's not governed by it. He governs it. So when this life is over, or even when earth is over, there is no time, aka "eternity." Without time, we won't be thinking, acting, or experiencing linear.
Therefore Judgement Day hits at once, except there is no "once" and there is no "day."
Depleted,
I really respect and appreciate your extremely high view of God, and of his sovereignty.
Sincerely.
However, the entire concept of time is just a horribly complex topic that has baffled philosophers since, well, forever.
If you don't think it's complex, just answer the simple question, "What exactly is time?"
If you think about it, you'll find it's extraordinarily difficult to answer.
Most secular scientists would define it in one way, but I think many theologians and philosophers, especially christian philosophers, would define it in a different way. I think most on our side of this debate would define time as a state that arises from "temporal becoming". This means the very act of change, and movement, is what actually causes time.
Even Plato, a very lost man, understood this several thousand years ago.
Change and movement will, and must, inherently generate the temporal states of "before" and "after".
If anything is happening, anything at all, then there is immediately, inherently, a "before" and "after".
This difference in before and after is what creates the "arrow of time", and seems to be the very genesis of time itself.
Therefore, time is generated by change and movement.
When God, the prime mover, first created, and first began the movement of all things... time was necessarily generated as an inherent result.
So what does this have to do with your statements about eternity?
Well, you suggested that when our lives are over, we go into an eternal state, where there is no longer time.
I don't think "eternity" requires the absence of time.
Let me explain.
From a closer look at time, I would suggest that when we enter into "eternal life", we also go into an endless temporal state, in which there IS time.... infinite time.
If we are moving and doing things, or if God is moving and doing things, or if any of God's creation is moving and doing things... then temporal time is necessarily generated in this process. (Change and movement creates the tensed states of "before" and "after"... and thus temporal time.)
I believe most theologians would hold that "eternity future" is something which does exist in temporal time...
and the present will gradually unfold into the "potential infinite" as we move into eternity in a completely temporal way.
Some of the terms I used above may sound odd, but I don't think I've expressed anything which is in any way unorthodox.
Any discussions of time and eternity are, by definition, very strange and tenuous.
God Bless