God judges us for our own sins
God told Jeremiah, "I the Lord search the heart and examine the mind, to reward a man according to his conduct, according to what his deeds deserve" (Jer. 17:10, quoted by Paul in Rom. 2:6). The Apostle warned that "for those who are self-seeking and who reject the truth and follow evil, there will be wrath and anger. There will be trouble and distress for every human being who does evil" (Rom. 2:8-9).
Paul seems clearly to assign judgment to actions:
All who sin apart from the law will also perish apart from the law, and all who sin under the law will be judged by the law. For it is not those who hear the law who are righteous in God's sight, but it is those who obey the law who will be declared righteous (Rom. 7:12-13).
Ezekiel 18:20 also states, "The soul who sins is the one who will die." According to Scripture, we are not condemned for the sins of others (including those of Adam), but only for the sins we commit personally.
We are in God's "book of life" from conception
The Lord keeps a "book of life" in which are written the names of those who will be with him in heaven. Moses said to God: "Please forgive their sin—but if not, then blot me out of the book you have written." The Lord replied, "Whoever has sinned against me I will blot out of my book" (Ex. 32:32, 33).
God has written your name in this book, and must "blot it out" if you choose to reject his free salvation in Christ. If you die without Christ, God is forced to remove your name from his book of life and you'll be "thrown into the lake of fire" (Rev. 20:15). Scripture is clear: "Nothing impure will ever enter [heaven], nor will anyone who does what is shameful or deceitful, but only those whose names are written in the Lamb's book of life" (Rev. 21:27).
Conversely, Jesus said to his disciples, "Rejoice that your names are written in heaven" (Luke 10:20). Paul addressed the Philippian Christians as "my fellow laborers, whose names are in the book of life" (Phil. 4:3).
In other words, at the moment of our conception our names are written in God's "book of life" and are removed only when we sin against him.
God judges us by our choices
But what of Romans 5:18-19? This text states: "Just as the result of one trespass was condemnation for all men, so also the result of one act of righteousness was justification that brings life for all men. For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous."
Is it not clear that Adam's trespass has condemned us all, that his disobedience has made us all sinners? No, actually. It's not.
Each verse is separated by a comma; if the first phrase applies to everyone, so must the second. If Adam's trespass condemns us all, Jesus' "act of righteousness" must save us all. If Adam's disobedience makes us all sinners, Jesus' obedience must make us all righteous. In other words, universal guilt must mean universal salvation.
The same logic applies to Romans 3:23, "all have sinned and fall short of the glory of God." This statement should be read in its context:
But now a righteousness from God, apart from law, has been made known, to which the Law and the Prophets testify. This righteousness from God comes through faith in Jesus Christ to all who believe. There is no difference, for all have sinned and fall short of the glory of God, and are justified freely by his grace through the redemption that came by Christ Jesus (Rom. 3:21-24).