What should a girl do who has impersonated fictional characters, including that of a man, to the extent that people have become attached to her, and now wishes to repent?

The door of repentance is open, and Allah rejoices in the repentance of His servants. Its first steps are to cease and abstain from the sin, to regret it, and to resolve not to return to it. Among the things that help in the sincerity of repentance and steadfastness upon it are turning to Allah by obeying His commands and avoiding His prohibitions, seeking righteous companionship, and staying away from bad company.