They changed over the summer, both of them.
Junpei had changed. More than he expected too, actually. He had grown a goatee, for one. He also had gotten really tall.
Chidori, on the other hand, had changed very little. Well, mentally speaking. Physically, she changed a lot. Her hair got longer—about half-way down her back—for one. She'd also gotten taller than she was but not as tall as he. She was just a little shorter than him, but not by much. Chidori had also become more… womanly.
Like any girl, her body began to become more like a woman and less like the girl he'd met that cold October day. She'd gotten curves, for one. Although she didn't do it often, there were times when Chidori wore a shirt or her pajamas, and those things showed the wonderful curves God had blessed her with. Chidori had also developed sizeable breasts, he noticed. He thanked the school she went too, or at least, the person who ordered the high-school uniforms, because those things were low cut. Not just the shirt, which gave a wonderful view, but the skirt was just long enough to cover her behind and her thighs, which gave the best view of her legs.
Not that he was a pervert or anything; just his observation.