This life isn't set in stone --- there is always hope.
Even though God the Father likely knew if we would be faithful and return to his presence or not before we were born, I strongly believe that outcome isn't set in stone.
God can see the future as it will be and I've always wondered if he ever intervenes and allows the possibility of changing the original outcome.
I believe we have our free agency to choose, but at times God will inspire and/or humble us so that we have time to reflect and consider a difference course of action that could ultimately change what will happen.
If this wasn't true, then why come to mortality in the first place, if God knew already if we would only fail or succeed as he could see into the future?
Sure you might need to have a physical body, but otherwise there's no reason to come to Earth if there no chance for a different outcome.
But I think because God does intervene to some degree, stopping short of taking any of our personal free agency away, that the outcome can be changed at many different points in our lives.
Thus, this means there is a reason to live a mortal life. The outcome is not set or certain yet. We repent or change the course as we listen to the spirit.
This hope alone is worth God letting us live our lives to truly prove if we are worthy to return to him.
(Note that this a different look on the subject of a similar blog posting I did int the past.)