To your relief, it does seem to fit! You pull on the blouse, and if anything it feels a bit baggy around the chest. You decide to try putting on the bra, doing up the clasp with it turned to face you and then turning the cups to the front and pulling the straps around your arms and find that the blouse fits better now. You tie the bow around your collar, and from the waist up you're wearing a neat Japanese schoolgirl uniform.
Next you pull on the knee-high socks, which you honestly feel pretty cute in, and step into the skirt before zipping it up around your waist. Noticing the panties on the floor, you wonder for a moment if it's really a good idea to wear them, but your curiosity gets the better of you. You slide your boxers off, a twinge of arousal hitting you as your hard penis touches the soft fabric of the skirt, and then pull the panties on.
For a moment, they don't fit, and you feel a little ashamed and like a perv for trying. But a moment later, the room around you seems to fade into bright and colourful lights. Your clothes vanish, and your body is naked as the day you were born, the odd light seeming to reflect across it. For some reason, this feels so good.
And before your eyes, your body starts to reshape to fit the uniform. You seem to slim down and suck inwards everywhere, except your hips, which seem to flare out and widen. Your chest feels sensitive, and the skin pricks up while your nipples become erect. Large mounds of flesh swell up as you form mammary glands that give rise to breasts.
Between your legs, the parts of you that prevented the panties fitting are receding away. Your testicles pull up inside you while your scrotum forms a flat mound that a vaginal slit emerges from, and your penis shrinks rapidly, its nerve endings binding tighter and tighter together until it has reformed into a tiny sensitive clitoris.
Once your body's transformation from boy to girl has finished, the void around you fades back into your bedroom. You look at yourself in the mirror in amazement- you've turned into a girl! You look and feel exactly like you've been one your whole life!
Given the way you transformed, you're left wondering- are you a magical girl now, or did you just magically transform into a normal girl? And can you turn back into a boy if you want? The answer is...