A Jedi Master who was female existed at some point between the years of 800 and 200 BBY.
Sometime around 800 BBY, a woman who could use the Force was trained by the Jedi Order in its practices, due to her being Force-sensitive. She achieved the title of Jedi Master, and at some point acquired a lightsaber that had been discovered on the deserted planet of Ossus. The method by which she obtained this ancient weapon was never explained by her; however, she gave it to her Padawan before elevating her apprentice to the rank of Jedi Knight.
- Dark Empire endnotes (Initial mention)