@XNovalX She's non-random enough to have been mentioned in last chapter and also figuring on book cover. So if she's a know-it-all then at least we've had warning XD
But another part hopes that this isnt their first meeting, and that she has known for a while who he is, supports his brother, and acts as his accomplice because they have been secretly dating eachother and MC just used this as a chance to make it official.