Alanna by Tamora Pierce

In this fantasy novel, a young girl defies the expectations of her society by disguising herself as a boy to pursue her dream of becoming a knight. She swaps places with her twin brother and enters the rigorous training program at the palace, where she must prove her worth in combat and magic while keeping her true identity a secret. Along her journey, she makes both friends and enemies, confronts powerful adversaries, and discovers her own unique magical abilities, all while navigating the challenges of growing up and finding her place in a world that underestimates her because of her gender. The 3404th greatest book of all time