Good story bringing up two very important things. You write it viscerally, which I feel is important. I also liked the juxtaposition to the excused pecking you had endured from your brother at this point in your life.

That said, it's also incomplete. How do we get from stealing the stuff of your desk to wanting to assault and/or rape you? He's 13 too, right? We're there actual spoken and specific threats? Sexual innuendo? Was this an assumption based on the following you and fear of how far he was willing to go if he switched classes? We're there other hints of possible sociopathic behavior or general creep behavior from poor impulse control? That performance, as you described it, was kinda creepy to me. Definitely raised an eyebrow there. I have a brother who got off on being a pest too, so I'm very familiar with the tactic and the appeal to a female authority figure. And how it usually plays into the favor of a boy who'd being abusive.