Time for something good to come out of all this bad.
You're sixty-one mostly miserable days into your sixteenth year, you want to take your wand and burn a hole in your twin's head where her oversized, witchy ego is, every kind of magic and spell-crafting seems silly-stupid or old-school (or just old), and sex (or the idea of it) is alternately horrifying or boring depending upon the day.
Mix in half-breed parents that are over-bright and over-stimulated (i.