Huh?

I can't decide on this issue and to be honest it is really confusing , as Calvinists o make a lot of great point s to prove their theory, yet I don't Necessarily agrees with the end result. In predestination there is insecurity ,because all men/women have been created in the image of God,and all men have sinned and fallen short of the glory of God.It is not by the amount of good (works) or evil(sin) that we have contributed to society ,but by the grace of God that we can be forgiven and saved. So if we are equal in those three ways than what does God think if predestination exists when he chooses who will be saved, and who will be forsaken.This uncertainty makes me question if I should witness to others knowing that it is God's decision has already be decided and, all I would be accomplishing is a false sense of hope if he/she was unfortunate to not be chosen. Or wonder if my friends and the people I care about arrive in the kingdom and I am left behind. This I know is selfish because it is God's will and not mine, but I worry now that in his plan I will not play a part in it, and how and why if we all are created equal than why will chose some and cast others aside .I just don't understand how that would be just.