Praise be to Allah.
Praying for concealment before going to commit a sin is asking that it be made easy and that one be protected from the consequences thereof. This is a transgression and is haraam, because Allah’s help cannot be sought to commit a haraam action.
Al-Qarraafi (may Allah have mercy on him) said in al-Furooq (4/296): 12: The haraam supplication that does not constitute disbelief – rather it is haraam because of what is being asked for. That is because it is asking that haraam actions take place. So if someone offers supplication and says, for example, “O Allah, let him die as a disbeliever, or cause him to drink alcohol, or help him to rob people, or help him to have intercourse with a particular non-mahram woman, or make it easy for him to attain a position of authority that incvolves sin”; or he prays against his enemy, such as saying “O Allah, do not cause So and so to die as a Muslim” or “O Allah, send against him someone to kill him or take his wealth”; or he prays for his friend, such as saying “O Allah, make it easy for him to attain a position of authority, or to travel to such and such a place, or to become a friend of a certain minister or king” – all of that involves different kinds of disobedience to Allah, may He be exalted. Therefore all of that is haraam because the means come under the same ruling as outcomes, so the means that lead to haraam outcomes are also haraam. If the supplication has to do with the worst kinds of evil, then it is the worst type of supplication, such as one who prays for a long life for an evildoer, which is a sign that he likes Allah, may He be exalted, to be disobeyed, because liking Allah, may He be exalted, to be disobeyed is haraam. This indicates that praying for something that is haraam is also haraam. End quote.
Ibn al-Qayyim (may Allah have mercy on him) said: Transgression in supplication may sometimes consist of asking for that for which it is not permissible to ask for, such as asking for help to commit haraam actions.
End quote from Badaa’i‘ al-Fawaa’id (3/524).
For more information, please see also the answers to questions no. 118750 and 301052.
What this girl must do is repent to Allah, may He be exalted, from her sin and her supplication, and not do that again.
And Allah knows best.