Predestination, true or false

Calvinism is the belief that God has predestined our future. So once a person is born, they are predestined to become a christian, or they are predestined to become an atheist. So they are practically saying that God gets to choose who goes to heaven and who goes to hell. Doesn't that sound wrong, that God picks people to go to heaven? If he chose that, then why not let everyone go to heaven? Why make us challenge the world through our struggles if we are just going to end up rotting in hell in the end? I don't believe that God would predestine people to go to heaven, it does say in the Bible that we are predestined by God but it also says that God gives us free will. So in the end, whether we go to heaven or not is through our earthly choices. Now, I do believe that when someone is born God knows the choices they will make,so he knows who will choose sin over righteousness/ hell over heaven, but those are because of our choices not because of the choices God makes for us. So I will stand on the side that is against Calvinism. Still there is the question about Paul's writing sin Ephesians. How I interpret it is that God has predestined us with the will to make our own choices. Also in Ephesians 1:5, it say's: "He predestined us to be adopted as his sons through Jesus Christ, in accordance with his pleasure and will". Now I don't see where it says we are predestined to go to heaven or hell, it say's we are predestined to always be with him. This can be in either heaven or hell depending on the choices we make. I believe this verse also applies to what the chapter says later on about how we are predestined to be chosen by him. We are all chosen to be with him that is what I believe Paul is saying, whether it be in heaven or hell, God will always be right next to us. So every choice w make is according to our own will, it is not predestined by God. So I stand on the side against Calvinism because I cannot believe in a God who chooses for people to suffer eternally in hell.