I'm not sure your response / understanding is altogether correct. Or, maybe it's a timing issue in your mind? Forgiveness is the Lord's and He will forgive whom he will forgive.
By not condemning her and commanding her to sin no more, Christ, in essence pardoned her in the moment, conditional on her "sinning no more." In other words, conditional on her repentance. This is the same gift He gives to each one of us through His Atonement.
Forgiveness for the repentant...