Mikey heard Shiela tell him that he should be a girl, and suddenly that was all that he could think about. He should be a girl. He was SUPPOSED to be a girl! He HAD to be a girl! Being a girl was the central truth of his entire universe!
That didn't mean that he 'wanted' to be a girl, per se, but rather that he simply needed to be a girl. But how?
Shiela's wish had been for them to just do what she tells them to do, and such, Mikey simply did what he'd been told to do, and became a girl.
Mikey didn't know, really, how he did it, but he could feel the changes overcoming him. They were all over, but mostly he could feel certain changes made him feel whole, even as they robbed him of certain... things, that he couldn't quite describe.
First he felt that his chest was tender, and when he felt it with his hands there was a perfect pair of squishy, rubbery, sensitive mounds there. Then he felt a stirring in his underwear. He could feel it as he pulled his thingy into himself, and that his boy parts were being re-made into girl parts. And he KNEW that they were girl parts, because with each change he felt more whole! More like a girl! He was coming closer and closer to fulfilling his one purpose in life! Even though he was moving farther and farther to what he'd been taught all his life to be. But what's teachings versus meanings?
She was a girl, a budding girl of some ten years old, just ready to take those next steps into puberty, yet having already developed just enough to be embarrassed about it. She was a tad taller than when she'd been a boy, since as a boy he'd had yet to hit his growth spurt, but that didn't really matter, all that mattered was the she was now a girl, and for the moment at least, she wouldn't have it any other way.