You are a student from the College of Winterhold, the College of Winterhold is the only school that has higher marking then Hogwarts.

The only way you made a silent half move to hogwarts Because your intelligence. You would switch weeks, one month at hogwarts one month at the College of Winterhold and repeat.

As you took your seat in the back of Professor Snape's class you listen and took notes. So far no students know about you being from the Collage of Winterhold, and only a few Professors know.