Gravlander by Erik Wecks

Synopsis:

Nineteen-year-old Josephine Lutnear is just months away from becoming the youngest fleet surgeon in history.

And she’s miserable.

As a young girl, Jo watched the Unity Corporation murder her family and barely escaped the moon Aetna’s destruction. Eight years later, the Unity started a war that left Jo running for her life. Alone aboard a hidden rebel fleet, she grew up studying the only academic course open to her: medicine.

The terms of Jo’s life have always been dictated by events beyond her control. Just once, she would like to make a choice all her own.

So when a band of genetic outcasts needs a doctor to cure a deadly plague, Josephine eagerly volunteers. But she will soon discover that the Timcree’s culture won’t accept help from a Gravlander like her. 
As her choices are once again taken away, Jo will stumble toward the truth—that she will never find purpose until she faces her past.