monitress

noun2

1. •
   (old-fashioned) A female monitor, or school leader.

   • Miss Mitchell would certainly be most relieved to have a monitress who was capable of organising the juniors at games. — 1922
2. •
   (no longer used) A female mentor or advisor; a female observer.

   • Diana filled up all his heart: he felt as if by his union with her he had received a new and better soul. She was his monitress as he learned what were the true ends of life. — 1820