Learning a song with 98% accuracy in the first 3 days is normal, right?

I have to upvote that.

Couldn't stop playing if I wanted to. Like it's my job.

I admire the dedication.

It's not dedication; it's addiction. When I was taking lessons from a very good teacher, she could not keep my gnat-like attention span captivated the way this game does. She taught me just enough so I could teach myself with this game without picking up many bad habits.