To qualify for Auror training, a witch or wizard had to first have attained at least five <a title="Nastily Exhausting Wizarding Test" href="https://harrypotter.fandom.com/wiki/Nastily_Exhausting_Wizarding_Test">N.E.W.T.s</a> of no less than 'Exceeds Expectations'. Minerva McGonagall recommended that <a title="Defence Against the Dark Arts" href="https://harrypotter.fandom.com/wiki/Defence_Against_the_Dark_Arts">Defence Against the Dark Arts</a>, <a title="Transfiguration (class)" href="https://harrypotter.fandom.com/wiki/Transfiguration_(class)">Transfiguration</a>, <a title="Charms (class)" href="https://harrypotter.fandom.com/wiki/Charms_(class)">Charms</a>, and <a title="Potions (class)" href="https://harrypotter.fandom.com/wiki/Potions_(class)">Potions</a> would be useful N.E.W.T. level classes for those wishing to pursue a career as an Auror.

Whereas the Ministry set a series of character and aptitude tests to further test the worth of potential applicants, it was also possible for someone to be offered a job in the Auror Office if one of its high-ranking and influential members deems an individual to have displayed sufficient ability to be qualified, although they still have to undergo the required training programme in order to become a fully-fledged Auror. The Ministry also runs a background check into the records of new applicants; Dolores Umbridge once implied that wizards with a criminal record cannot become an Auror.

It will be usful if you know how to read Ancient Runes, or at least are learning it. First years? I am sure that you can take the Runes still. However, you don't have to.