"I wish that I was always as old as Karyn!"
Once again, Karyn found herself having to look away. She turned back to see the familiar Jon, as old as he was this morning. No, wait. Jon was only as old as Karyn now, which meant he was a bit over two months younger now. Luckily, it seemed no one had noticed the change; Jon had made his wish quiet enough. She snatched the stone away before he could make another one. "What a waste of a wish. I control your age, remember?"
"Nope," Jon stated with a triumphant smile. "I thought about this a lot. It wasn't like I could do much else, as an eight year old, or a baby. I wished to always be as old as you. That means you can't change my age anymore!"
Could Jon be right? The stone couldn't undo other wishes... but Jon's changes in age were only indirectly due to the stone. Could she still change how old he was? There was only one way to find out. "I warned you what would happen if you caused any problems, you disobedient little boy," she said with a scowl. Karyn had to put up with her new hair and breasts permanently, it was only fair that Jon spend a day at a different age. She did a quick calculation with her current age -- as Jon would now share a birthday with her -- and said, "Minus..."