You mention that the mentally retarded and very young are exempt from even knowing there is a God. I understand that. Can you tell me your thoughts on how young?
I have a nine year old son who has grown up in the church and who I and his father consistently talk with about God, Jesus, sin and the message of salvation. But, he has not made a profession of faith. I know that part of him is a little fearful and embarrassed to be baptized. We talked at length the other day about the fact that just because we (his parents) are saved this does not extend to him. He has to make the decision in his heart for himself. He asked me where he would go if he died right now without having made this decision. What do you think?
The answer to your question depends on whether a reasonable adult would, after having a conversation with your son, conclude that he demonstrated a thorough understanding of sin, heaven and hell, what it means to be saved, the provision God has made for man’s salvation, and the necessity for each of us to apply it personally.
If he can demonstrate such an understanding, then if he died today he’d be lost. You might explain to him that the decision to be saved and the decision to be baptized are not the same and can be two separate events. He can make the decision to be saved in the privacy of a conversation with you as soon as he’s ready and then be baptized later, when he’s more comfortable with it.
Remember, the Bible says we are included in Christ when we hear the gospel of our salvation and believe it. At that time we receive the Holy Spirit as a deposit guaranteeing our inheritance (Ephes. 1:13-14) which is eternal life. Being baptized is a public declaration that the private decision to be saved has been made and can take place at a later time.