You said that the very first sin brings spiritual death is that a known or unknown sin? Secondly Paul says we were all dead, 2 Corinthians 5:14 For the love of Christ constraineth us; because we thus judge, that if one died for all, then were all dead:
Paul says "then were all dead" if not spiritually then how?
15And that he died for all, that they which live should not henceforth live unto themselves, but unto him which died for them, and rose again
I believe the person is covered until they come to a knowledge of sin as I showed with Adam and Eve. But I believe they are born spiritually dead and with a sin nature. Innocence not having knowledge of sin is what protects them just as it did Adam and Eve, until they had knowledge of good and evil.
Paul again reinforces this as spiritual death and an old sin nature in the very same Ephesians chapter
Ephesians 2: 3 Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others.
4But God, who is rich in mercy, for his great love wherewith he loved us,
5 Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved
v3 By nature we are children of wrath (Old Sin Nature), v5 "we were dead in sin". We born the children of wrath and dead, Paul tells us here.
Christ avoided spiritual death and the Old sin nature because of His Father, because the earthly father passes on our inheritence and Adma sinned and brought death, Eve was decieved and doesn't pass the OSN to her children, nor would she (woman) pass on Spiritual death.
Even though all chidren are born spiritually dead and have an Old Sin Nature they are covered because they have not gained knowlege of good and evil.
