Harry Potter riddle: Who am I?

I'm pretty sure it's the sorting hat. He is a legilimens, he sings a new song every year, looks are deceiving because he looks old and tattered but is very smart, and is over a century old.

"Oh you may not think I'm pretty, but don't judge on what you see, I'll eat myself if you can find a smarter hat than me."
—The Sorting Hat