Girls can be heroes too.
By giving Aerin a plenary hero's journey, McKinley shows that gender roles don't need to inhibit women from being adventurous and from saving the day. Aerin is nothing short of a hero to her nation, and her ability to persevere is admirable. The plot is like a Joseph Campbell-type myth, but with the character's genders flipped. Notably, Aerin's mother herself rejects her daughter and dies, but in the end, Aerin proves that girls are just as capable.
Rejection, confusion, and loneliness are temporary.
If Aerin would have quit when things were hard, then she would have stayed a reject forever. But instead, she made herself into a powerful person. She practiced for three years and then bravely fought a dragon. After finding herself, slowly but surely, she becomes greatly powerful, and the kingdom depends on her for their survival.
Slaying the dragon.
By slaying a small dragon, Aerin gains experience. By bravely defending the kingdom from the great dragon, she gains a powerful relic. All these small victories add up to her ability to defeat the warlock Agsded and earn herself a position of power in a new era of Damar history. She gains power each time she steps out in faith and succeeds, and each victory makes her more willing to take on a difficult villain.
