Jacob was 15 when Abraham died, 50 when Shem died and 120 when Isaac died. Abraham would have had the opportunity to share his knowledge with Jacob as a young man, I know if I knew Shem I would want my children to meet him. I cannot imagine Isaac not taking them to visit with him. Jacob would have had interaction with Abraham, Shem and Isaac, all men who knew God personally.
As with all men Jacob still needed to follow the pattern, exercise faith, and be prepared to come into the presence of God. As far as I can tell Enoch, Noah, Abraham, Isaac and Jacob first came into the presence of God when they were older than 60. They did not do nothing in those years. They raised families, were tried and tested with the temptations of life and they were taught by others about how to worship God and have faith in the Messiah. Each had to choose for themselves and then remain faithful during trials. Their siblings would have had the same opportunities however each person must choose for themselves.
There is much more written about Jacob and yet there are many interpretations of what he was like. The fact remains God deemed him worthy to be in His presence. That does not come from wickedness, it comes from a life of righteousness, from putting God first, obeying God and strengthening one's family and others by pointing them to the Father.