As Augustine stated understanding predestination isn't difficult if one start from the premise that everything we are (eg thoughts, attitudes, desires, faith, etc) were all given to us by God. God designed us just as we are. There is nothing we have that hasn't been given to us by God.
What we don't understand is why God designed us like we are.
Except that which the Protestants deny -- free will. Then how can we have a mind? Why do we need a mind? If we have no free will, we cannot commit sin. If we cannot commit sin, what was man's fall all about? If we cannot commit sin, why are we being punished? If we did not commit sin, why do we need to be saved? If we are no different than animals (driven by necessity and not by reason), why did God suffer and die for our sins that we didn't commit to begin with?
You see the whole Protestant notion falls apart on its own nonsense.
If God is omnipotent why can't He change His mind? Is God not free to change His mind? Is God's plan holding God hostage? Whatever God's Plan is, He will accomplish it and indeed has already accomplished it! Getting there in real time is a matter of taking whichever route He sees fit for us.
Our free will was given to us for us, not so that God would accomplish His plan. We cannot change or cause God's plan to fail no matter what choice we make. We can, however, affect our own salvation by cooperating with God, or our damnation, by refusing Him.
Remember: God has an infinite number of options and they all lead to the accomplisment of His already accomplished plan. We only have two choices: God or no-God. He gave us the ticket. One train goes to heaven the other to hell. It's up to you which train you will pick. It does not change God's plan at all!