Question:

If a person isn't baptized, does that mean that they've never been forgiven of any sin they've ever committed?

Answer:

"Then Peter said to them, "Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit" (Acts 2:38).

"And now why are you waiting? Arise and be baptized, and wash away your sins, calling on the name of the Lord" (Acts 22:16).

"Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death? Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life. For if we have been united together in the likeness of His death, certainly we also shall be in the likeness of His resurrection, knowing this, that our old man was crucified with Him, that the body of sin might be done away with, that we should no longer be slaves of sin. For he who has died has been freed from sin" (Romans 6:3-7).

"There is also an antitype which now saves us--baptism (not the removal of the filth of the flesh, but the answer of a good conscience toward God), through the resurrection of Jesus Christ" (I Peter 3:21).

Under the covenant of Christ (the New Testament), salvation from sin is given as a gift to those who have heard the word of God, believed that Jesus is the Son of God, repented of their sins, confessed that Jesus is the Son of God, and are baptized into Jesus' death. The Bible doesn't teach multiple roads to salvation and the final step for forgiveness of sins is baptism.