At my salvation experience I did not even know the bible,did not come from a christian home, I simply asked God what He wanted me to do,immediately I was engulfed in intense love and God spoke to my mind saying,you must accept My Son as your Saviour. The Lord went on to explain that in my present condition I was headed for hell but I would be saved if I commited my life totally to God and confessed Jesus as my Saviour before the church. After doing this God began to speak to me from my lower chest area saying over and over,"you are My child and I love you".Why did you believe? Was it because of your wisdom? You were wise enough to discern the truth of the matter but others who heard the same Gospel were not? Was it because of your self-control? You willed yourself to faith while others couldn't muster the effort needed? Tell us please. Why did you accept Jesus?
It was interesting that God told me that in my present condition I was headed for hell,also God presented to me the way to be saved and then insisted that I make the choice. There is no doubt in my mind that I could have said no,in which case I would now be headed for hell because I would had rejected Christ.
You are trying to understand something that only God understands,exactly WHY one person will accept Christ while another will not...the "you were picked before you were born premise", is just a man created idea to try to explain what cannot be explained in this life.