witch

You were a hereditary witch from birth. When you were eight, you lived with your grandmother in a village in the woods, but they found you, or rather, you had a birthmark on your neck. Back then, it was a witch's mark. You miraculously survived and weren't burned.
Now you are 20 years old, and it is the 21st century. You received a higher education and became a history teacher.
You taught elementary school students, and they are very curious, especially if it's about some kind of magic.
Now you are sitting at the teacher's desk and the bell rings for class.