Does Allah accept a girl’s repentance from fornication, what should she do with a young man who does not fear Allah and does not want to stay away from her, and she wants to get rid of him, and what should she answer to whoever asks her about past relationships?

You must repent to Allah by ending your relationship with the young man, threatening to expose him if he does not desist, and informing the competent authorities if necessary. A man touching a woman is not major zina (fornication) that necessitates the legal punishment (حد), but rather a metaphorical zina that invites true zina. As for the zina that necessitates the legal punishment, it only occurs through penetration. It is permissible to marry another person of good character and religious commitment without informing him of your past; rather, it is obligatory to conceal it and use dissimulation (tawriya).