Ok, from what I believe scripture teaching, from God's standpoint, sin was forgiven on the cross. My believing in Christ does not activate anything of God. God activates me to what he has already done. In other words, my believing in him and repenting is not so that I can get forgiveness of sin applied, but it is in response to the fact that sin has been forgiven by Christ on the cross. The Bible is clear. "I will remember their sin no more," not, "I will tentatively remember their sin no more, in limbo, waiting until they repent."
There is no more sin or consciousness of sin from God's standpoint. That is made very clear in Hebrews chapters 9 and 10. That is why only one sacrifice is needed, and it truly did what it was supposed to.
But here are a few other scriptures which relate specifically, although without revelation you will not believe it.
1)All were in sin at one time, in Adam.
2)When Christ died, all in Adam died with him.
2Co 5:14 For the love of Christ constrains us; because we judge thus, that one died for all, therefore all died.
3)Because all died, the penalty of sin cannot be applied anymore to anyone.
Rom 6:7 For he who has died has been freed from sin.
Eph 2:5 even when we were dead through our trespasses, made us alive together with Christ (by grace you have been saved),
That is everyone, because that event in time, Christ's death, was my death, and your death, everyone in Adam died that day. Notice that together with Christ we have been made alive. But until God opens our eyes to see it, we remain as children of wrath, of the devil. Each, in God's own time, will have his or her eyes open, NOT to be forgiven of sin, for there is no sin to be forgiven of in God's eyes. There is NONE! There is no more dying in your sins AFTER the cross. That is how I understand it. Mankind is only in sin in his own deluded thinking.