...someone in feudal Japan. That sounded cool to Ty- he had a bit of an interest in historic Japan, so figured getting to live there would be pretty fun. As he developed, he wondered what it'd be like to train as a samurai and wear cool armour, while in his head he saw his perception of himself change so he had a more slim, trim figure and Asian skin tone and hair and eye colour.
Slowly Ty became aware of something that felt... different that came from the sperm that had fertilized him. It had nothing to do with his ethnicity changing, so what could it be? Gradually it revealed itself to him, first through a growing sense of distance from masculinity and soon by seeming to pass up something Ty had always considered innate. Ty soon had to recognize why all this was taking place. The sperm which had formed this body had an X chromosome.
Ty's self-perception altered rapidly as his body turned from male to female. His muscles turned more petite and his figure more curvaceous. His facial features softened and much of his body hair vanished. His chest enlarged as breasts developed atop it and his nipples developed into mammary teats. His penis shrank and shrank and grew more and more sensitive until it formed a clitoral nub. His testicles moved up inside his body and linked up to a female reproductive system, while his scrotum reshaped into vaginal folds.
While all these changes occurred, Ty felt more and more of a sense of emasculation. He wouldn't be a boy in feudal Japan, she would be a girl in feudal Japan. And she had a feeling she'd have to use her power a lot to keep herself safe and especially happy. Thankfully, she at least got to discover something that felt unquestionably nice: attraction to guys. Her sexuality reversed itself along with her sex, and it kinda clicked with her why people found handsome firm bodies and big hard penises attractive. The idea of someone fucking her one day felt appealing all of a sudden.
Having said that, it would definitely be 'one day', because Ty now felt herself get released from her new mother's womb into the world, and the intense surge of cold made her weep uncontrollably. She saw her new father sever her umbilical cord and her new mother cradled her before offering her breast, which Ty suckled on, comforting her. Ty knew she wanted to age way past infancy, so decided to age herself up to 18, wondering what role she would have...