I don't remember where in the Bible, but it does in fact say that when you don't understand something you aren't held accountable. But when you do understand and comprehend something then you become responsible. This to me means that innocent children must be forgiven for their mistakes but when they are taught that something they have done is immoral, then they become responsible and have the burden of doing right. This is why after learning about the fall of man in Genesis 1-11, should read Psalms and the New Testament to learn about Jesus the perfect sacrifice and savior. Also that God desires mercy not sacrifice. We don't have to sacrifice our lives, no suicide, no sacrificing children, animals, or other valuables. Instead give freely to others that you would have them give to you. Wash your brother, sister, and mother's feet. Help with chores, and when you go to serve God in another land, heal people in Jesus Christ's name.

Jesus said, unless you enter like a child  in my Kingdom you will not enter the Kingdom of Heaven

Also, one have to acknowledge Jesus before the Father in Heaven.  One that denies Jesus also denies the Father and will not enter the Kingdom.  If we denies Jesus before others , so will Jesus denied us before the Father.

He also said, that we have to forgive others with all our heart in order to be forgiven by Jesus our Lord

When Jesus comes again into His Glory, then He will separate people from one another, the bad and the righteous and according to our acts in earth He will recompensate us.  Not everyone that saids, Lord, my Lord will enter the Kingdom of Heaven.  The main thing in our lives is to seek Jesus, do the right thing and never stop not even a moment striving for that day in which we will meet Him and see His face and pray to be with Him in eternity.