The Warrior Maiden by Melanie Dickerson

Book 9 of  Hagenheim

Summary: 

A reimagining of the classic Mulan tale in medieval Europe, where both love and war challenge even the strongest of hearts.

When Mulan takes her father’s place in battle against the besieging Teutonic Knights, she realizes she has been preparing for this journey her whole life—and that her life, and her mother’s, depends on her success. As the adopted daughter of poor parents, Mulan has little power in the world. If she can’t prove herself on the battlefield, she could face death—or, perhaps worse, marriage to the village butcher.

Disguised as a young man, Mulan meets the German duke’s son, Wolfgang, who is determined to save his people even if it means fighting against his own brother. Wolfgang is exasperated by the new soldier who seems to be one step away from disaster at all times—or showing him up in embarrassing ways.

From rivals to reluctant friends, Mulan and Wolfgang begin to share secrets. But war is an uncertain time and dreams can die as quickly as they are born. When Mulan receives word of danger back home, she must make the ultimate choice. Can she be the son her bitter father never had? Or will she become the strong young woman she was created to be?

Opening Lines: 

Galloping her horse past the big oak tree, Mulan pulled the bowstring taut. She aimed at the knothole with one eye closed and sent the arrow flying toward the target. it struck the tree but missed the knothole. 

"Don't shoot behind you!" Andrei flailed his skinny arms. "Keep the target in front of you." 

Shooting from a moving horse was much more difficult than when standing still, but she was improving. At least she'd escaped, for the moment, the cooking and cleaning chores. And practicing war skills kept her from facing the uncertain future--and her mother's grief.