You're a foot taller

Fair enough, it's not that you can see something odd in the mirror. More accurately, you can only see your shins in the mirror, as you are now a head taller than it.

Sophie: "Heeeyy... what gives?"

You don't remember having contacted giantism in the recent past. Nor do you recall going through agonizing growth pains last night. In fact, you feel so excellent! You don't even look like a regular tall human, your proportions are still exactly the same.

Sophie: "Welp, looks like magic is real. Still waiting on my letter to Hogwarts, though. And to be honest I think they'd rather have me as the groundskeeper now..."

You're not really sure how to deal with this.