All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is permissible to marry a female who committed Zina provided that two conditions are met: repentance and Istibraa’ (i.e. she is confirmed non-pregnant).
If this girl is a Muslim and she repented of Zina and fulfilled the due conditions of repentance, meaning showing remorse, giving up the sin, and resolving never to commit it again in the future, then it is permissible for you to marry her to guard your chastity and hers after she is confirmed non-pregnant. Among the most important conditions for the validity of marriage are the consent of the Wali (guardian of the bride) and the witnesses.
If she is a Christian or Jew, it is permissible for you to marry her if her sincere remorse over committing Zina becomes clear to you and she is confirmed non-pregnant. In this case, her Wali should be of her religion. Although marriage to a woman of the People of the Book (Christian or Jew) is permissible in Islam in principle, some scholars deemed it disliked for many reasons, including the potential consequent risks with regard to raising the children, especially in the event of divorce and separation.
Allah Knows best.