We exist in time as a journey, a becoming. Our lives, with what we are given and choose to do from beginning to end, exist eternally in the mind of God.
God is the eternal Ground of all Being. He brings into existence all time and all space. Doing so, He is outside His creation. In the same instance, He also reaches into it through the Holy Spirit, as loving Father and in Jesus Christ who became one of us.
Unchanging as the Source of all there is and encompassing everything that is in every time, He in eternity knows all. There can only be one reality. If for His reasons, He told us of the future and not of possibilities as He does when speaking to Cain, encouraging him away from sin, it would happen, because He right there bringing the event into existence, permitting it to happen in accordance with His omnipotence and omniscience.