Once upon a time, Arya Stark was a stupid little girl.
She'd chafed at the restrictions of noble life, muddied her best gowns, stolen knives from the kitchen and practiced throwing them in the stables, and preferred the company of servants to other high-born ladies, who only liked talking about cute noblemen and their clothes. During dull calligraphy or embroidery lessons, while Sansa paid rapt attention, she'd daydreamed about being a knight and learning how to fence instead, just like heroes in ballads did.
When she went south to King's Landing, she wasn't yet disillusioned, not even when she had to run from Prince Joffrey's men and found that the wilderness was far from a comfortable place to hide, not even when she realized that the court was a snake's den full of those who would gladly slit her throat for a shred of power. She had begun to study swordplay at the same time, and was naive enough to believe that with Needle in her hand, nothing could possibly hurt her.
Then she'd watched as the Lannisters beheaded her father at the Great Sept of Baelor.
Her father, who'd understood her more than anyone and didn't laugh at her most fervent desires. Her father, the one of the only people she'd ever truly loved. Her father, who'd always seemed invincible, untouchable.
Her father, whose corpse was defiling the sept with too-bright crimson blood that sparkled in the sunlight. Dead before a house of gods foreign to him.
And suddenly, little Arya Stark was forced to use her blade for more than sparring practice or chasing pigeons. She discovered what it meant to be cold and hungry and unsure about whether you would survive until the next day. She was free of noble limitations, because out in the war-torn countryside, nobody gave a shit about whether she held her fork correctly or not. They were too busy trying to see if they could spare a morsel of food for a skinny beggar with twigs in her hair and disaster in every curve of her face (most of the time, they couldn't.)
Fear cuts deeper than swords.
In the end, she got her wish.