The Gift of Magic — P.M. Griffin

An outburst of her newly awakened, uncontrolled sorcery talent made twelve-year-old Dory a fugitive. Trouble, her indomitable cat, led her into a walled garden minutes ahead of the mob pursuing her. There they encountered Martin, a powerful sorcerer, who agreed to hide and teach her and used his arts to advance her age to that of a young woman.

Some weeks later, Martin permits her and Trouble to accompany two gem merchants on a trading voyage. Following a storm, their ship goes to the aid of a sinking vessel grossly overcrowded with young migrant workers. The rescue is a success, but Dory's ship is seriously damaged and begins founderin. With no room in the lifeboats for all those now aboard, many are doomed. Only Dory's untried power can save everyone â€" if it will rise for her and if she can control and wield it correctly.