You're Hermoine's sister and got into Hogwarts, she's introducing you to Ron and Harry

Hermoine: She's my sister, Y/n. Y/n these are Ron and Harry.

You guys exchange handshakes etc and talk.

Draco and his friends where they're not so far away from you, chatting about you. Draco think to himself; "Look at that pretty little face, she just looks like a doll...damn, I'm hooked. Can't believe that I'm thinking of a mudblood. She just makes me wanna go..."

Draco let's out a whistle

While Hermoine kept introducing you to Ron and Harry;

Hermoine: And guess what, she can read minds!

As she said, you knowing everything Draco thought let out a whistle, copying his.

Draco freezes for a moment