Does a mistake at the beginning of a relationship—which developed from an online acquaintance to an in-person meeting with mahrams, and then paused with the intention of transforming into a legitimate marital relationship—necessitate its complete termination, especially given that both parties have repented and changed their behavior for the better?

Familiarity between young men and women for the purpose of marriage is a gateway to temptation. However, the error that occurred does not prevent marrying the girl if she is religious, and sincere repentance erases the effect of sin. The questioner is advised to convince his father to marry the girl. If the father insists on refusing, then he must turn away from her, unless there is harm to him in abandoning the marriage to her, for obedience to parents takes precedence, especially if the father's refusal is justified. As for the father's desire for the questioner to marry his relative, if she is righteous and acceptable to him, then marrying her is more fitting. Otherwise, he is not obligated to obey him in that, and he must honor his father and be kind to him in all circumstances.