Are a student's grades in an exam written with Allah, such that they neither increase nor decrease, and is her academic outcome predetermined, unchangeable by her diligence?

Allah’s preordainment of destinies is not an excuse to abandon taking means. The Prophet (peace be upon him) commanded action, clarifying that everyone is facilitated for what they were created for, and that the people of happiness are facilitated for the deeds of the happy, and the people of wretchedness for their deeds. The believer is required to be keen on what benefits him religiously and worldly, and to seek Allah’s help and abandon helplessness, for the strong believer is more beloved to Allah. If he is afflicted with something he dislikes, he should say: “Qaddara Allahu wa ma sha’a fa’al (Allah has decreed and what He wills, He does)” to avoid the work of Satan, which the word “if” opens the door to. This hadith includes the principles of faith: being keen on what benefits along with exerting effort, seeking Allah’s help, abandoning helplessness, and accepting divine decree. Therefore, one must seek Allah’s help, purify intentions, and exert effort in seeking knowledge.