"The Woman Who Rides Like A Man" by Tamora Pierce
(from the back of the book)
Newly knighted, Alanna of Trebond seeks adventure in the vast desert of Tortal. Captured by fierce desert dwellers, she is forced to prove herself in a duel to the death--either she will be killed or she will be inducted into the tribe. Although she triumphs, dire challenges lie ahead. As her mythic fate would have it, Alanna soon becomes the tribe's first female shaman--despite the desert dweller's grave fear of the foreign woman warrior. Alanna must fight to change the ancient tribal customs of the desert tribes--for their sake and for the sake of all Tortall.
This is book 3 of 4 of the series Alanna: The first Adventure. Alanna wanted to be a knight instead of going to court and marrying a nobleman. So Alanna hides her identity and goes off to become a knight. She passes her test to become a knight. After she kills her arch enemy Duke Conte', her identity as girl becomes known. Alanna leave Tortal to find adventure.
She finds her adventure with the Bizar tribe people. She must prove herself worthy of becoming one of the tribe. She also has someone there who thinks she is evil because of her magic. The Shaman of Bizar wants to kill Alanna. But Alanna kills the Shaman, thus opening the way for her to become the tribe Shaman. She takes three outcasts and teaches them the magic and they become Shaman's. During all this Prince Jon comes to the Bazir tribe to become The Voice of Bizir Tribe. He also asks Alanna to marry him. Alanna is not ready to marry and Jon goes back home to court someone else. Alanna is sent to find a friend of headman of the Bizar and finds her next adventure. That will be Book 4.
For Week 16