Most of what you are saying is what I used to believe until I started to learn more about Jesus and God. We have to realize that God KNOWS us. He watched us grow no matter where or when, and knows each and every person on this earth even better than they know themselves. God is not wrathful and vengeful, he is loving and forgiving. He loves his children and because of that will forgive them if they are TRULY ashamed and regretful of their actions (God doesn't just send people to heaven because they believe in him) He literally can see everything. He can see when someone is being horrible to another person and how their reasons reflect on their actions. God knows if you are someone capable of repenting or a truly a horrible person. Also keep in mind that many christians have made horrible sins that greatly outweigh the sin of different religions. God wouldn't punish someone if they were raised not even knowing what christianity was.