Karyn's mom pushed the door closed, but Jon pushed it back open and rammed his way past her and straight to Karyn. He wasn't about to miss out on this opportunity. When he got close enough to Karyn, he began to change. First he became younger, back to sixteen, then his clothes changed to match.
"Oh. Hi, Jon," Karyn's mom said, from behind him. Then she walked out of the hallway and into another room.
"Karyn," Jon said. "Do you know about the wishing stone?"
"What kind of question is that? Of course I know about it. Where do you think I got these from?" she asked, pointing to her breasts. "Thanks to that stupid rock, I had to go out and buy larger bras."
Jon was relieved. Things were back to normal, at least for the moment. "Let's go to your room," he said. "I have something to tell you."
They walked down the hall and then into Karyn's bedroom (her house was only a single floor house, so her bedroom was on ground level). Then Jon closed and locked her door. This was private, he didn't want anyone else to know about the stone. And he certainly didn't want someone barging in and changing him before he got a chance to explain everything to Karyn first.