Ty decided it'd be nice to just see himself turn into a girl to start with. So he shut the closet door and wished into existence a large mirror he could see himself in. He undressed until he stood before it naked, and taking a deep breath, he said, "novi femina."
A shiver ran through him as he felt his body respond to the words, his skin almost seeming to ripple like water and an odd clenching sensation enveloping him. He turned more petite all over, his arms and legs and figure more small and resembling a girl his age's rather than a boy his age's. His shoulders sloped inwards and his hips shifted outwards, his ass filling out in conjunction with them. He saw his facial features subtly change, and realized he saw a girl's face in the mirror rather than a boy's. His skin seemed softer, smoother, more supple to the touch.
The changes then focused on the last male parts of him, his chest and his crotch, and he breathed heavily, his head swimming with indescribable sensations as the hormones that filled him inverted themselves rapidly. His nipples grew larger and puffier, and the desire to have them played with emerged in his mind. His pants grew softer and higher-pitched as soft mounds formed on his chest. Further down, his penis had begun to shrink into itself, its nerves binding up tighter and tighter together as the phallus receded to a sensitive nub. His balls moved up inside her and the skin sac that had contained them shifted inwards until it peeled open to form vaginal lips.
When Ty looked at herself, she felt amazed to see and feel completely like a girl. Naturally, it felt like nothing else she'd ever experienced, and yet it was as if she'd always been this way- her brain had even adapted to think of her as female. Her body was about as scrawny as his had been as a boy, but it felt right to see herself as a girl. She was sure it'd feel even more right when she tried on some of these clothes, and wondered what to pick first...