Legends of Belariath
Skyla
Skyla's fascination with the way of the warrior at a young age, spending warm days laying in the shade watching them practice and spar. Days her mother would have preferred she spent learning more proper "womanly" pursuits. Disdaining such thoughts, Skyla made her plans to learn the way of life that called to her.
Once she had reached an age that the boys of her village took up the sword, she snuck from home to join with the trainees. She got to the fields with the others, lined up for inspection. Little did she know of her mother's meddling, or the trainer's previous disdain for female fighters. When the trainer got to her, rather than the legitimate inspection and testing, she was instead mocked and given a punishing fight to 'test' her innate ability with the weapons, leaving her bruised and ashamed, but also angry and determined.
She continued to return, day by day, suffering more mocking and bruising punishment that grew more intense as her stubbornness became apparent. Eventually the trainers began to simply turn her away, and ignore her attempts to join in the training. Seeing the new tactic being employed by the people she saw as holding her back from her true calling, Skyla chose to change her tactic.
Going to the trainer of magic within the village, another woman of unconventional means, Skyla asked to be taught the spell to change her gender, to fool the warrior trainer. Being amused at the thought of the weapons master being fooled by the girl, the female mage agreed to assist her, and not to tell others of her new knowledge. Once Skyla mastered the spell, she snuck from home once more, and cut her hair short before she cast her new spell to attend the training sessions once more.
Without the bias and taunting of the trainer, Skyla quickly learned and progressed in the use of weapons and fighting. She quickly matched and surpassed the other trainees in the months to come. The months turned to years, and the years quickly brought her to the age of majority, when she decided to return the mocking to her trainer for her initial humiliations. Upon her graduation from training, with the other trainees, she stepped forward to challenge the trainer one last time. She drew the fight out, tiring the trainer out while maintaining her own energy. Once the trainer began to wheeze and grow sloppy in his frustration, the warrior-in-disguise mentally dispelled her gender swap and gave him a mocking salute before beginning to return the bruisings he had given her so many years before.
From there her life changed dramatically, her mother turning away from her and refusing to attend her coming of age ceremony, and the joining of her soul and body. Once she had fully become an adult, she left behind the village that she felt was holding her back her entire life, to seek out the wider world and the adventures that it held for her.