Unlike Aang or Korra, who were taught bending from the time they were children, Kyoshi had a very unique upbringing that prevented her from beginning her training until she was a teenager. The child of two Daofei bandits, Kyoshi spent her earliest years traveling until she was abandoned in a poor fishing village. She lived alone on the streets until Kelsang — an air nomad looking for the next Avatar — found and began to care for her. Though she took the Avatar test, she never completed it, and worked as a servant at the Avatar mansion until she was 16. Meanwhile, another boy, Yun, was falsely identified as the Avatar.
Things changed, however, when a group of pirates attempted to capture Yun. During the conflict, Kyoshi’s Avatar abilities awakened, and Yun’s true nature was drawn into question. It wasn’t until a man named Jianzhu used an evil spirit to confirm the real Avatar that Kyoshi learned the truth. After Jianzhu killed Kelsang and left Yun for dead, Kyoshi ran away to join her parent’s old gang, the Flying Opera Company.
It was then, at 16 years old, that Kyoshi finally began her Avatar training. The gang taught her earthbending and waterbending, while Yun’s old bodyguard, Rangi, taught her firebending. Another year would pass before Kyoshi finally revealed herself to the wider world, and journeyed to the Southern Air Temple to learn airbending.