I see the point you are making, and you are correct in a sense. You are correct that God knows exactly what will happen in our lives. Looking from God's point of view, you are right. However, we as humans cannot look at things from God's point of view, so we must look at them from our own. From our point of view, we cannot see the future, so we do not know what is in store for us. We make our decisions based on the free will that He gave us. He knows what we will choose and what the consequences are, but we don't. Therefore, looking from our point of view (which is the only one we have), we have the free will to make decisions that affect our lives.
I think your idea of predestination is that we follow a script that we cannot escape. Maybe so, but since we don't know what it is, from our POV we have free will. For example, you can choose to shoot yourself today and die, or you can choose not to. Since you don't know which one you are predestined to do, you have a choice. God knows which one you will pick, but you have the free will to choose.
...what would Jesus do in this situation ? ...
The Book of Life is already writen in God's infallable knowledge.
Just because you can't see it ( but God can ) dosen't make the empty seat waiting for you any less real.
... with a tip of my hat to Schrodinger's Cat