An Unexpected Apprentice — Jody Lynn Nye

Halfling Tildi Summerbee has led a typical, unexciting life, tending the house for her brothers while they manage the family farm. Her days are boring, but happy...until a Thraik attack decimates her family.
In an effort to provide for Tildi, the town's leaders prepare an arranged marriage and take control of her farm's assets. After all, a female halfling is incapable of handling such matters on her own.
Tildi sees things differently.

In order to escape her arranged marriage and overcome the prejudices against the "weaker" sex, she decides to pass herself off as a man. Assuming the guise of her brother Teldo, Tildi disappears into the night. She plans to accept Teldo's position as an apprentice to a great wizard.
But she soon finds that the rest of the world isn't very welcoming to halflings. And that she is surrounded by fantastic dangers.
Dangers that are more than a match for a wizard's apprentice.