Can a girl who committed many sins before knowing Islam convert to Islam, and what should she do about her past life?

Allah, the Exalted, is the Forgiver of sins, the Acceptor of repentance, and the Severe in punishment. Ibn Abbas narrated that some polytheists who had committed major sins came to Prophet Muhammad (peace be upon him) and asked him about expiation for their sins. Thereupon, the following verses were revealed: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.' And return [in repentance] to your Lord and submit to Him before the punishment comes upon you; then you will not be helped." (Az-Zumar: 53-54). Moreover, it is stated in the Hadith of Amr ibn al-Aas (may Allah be pleased with him) that Islam nullifies what preceded it in terms of sins, meaning it erases previous sins. Therefore, Allah erases all sins through Islam, and one's record becomes clean. Hence, one must hasten to embrace Islam and repent.