Immediately after the stone glowed, Jon started to panic, as he felt himself getting smaller and smaller. Even his clothing was changing. "What's happening to me?" he asked aloud, hearing his voice getting less and less mature by the second.
When he finally stopped getting smaller, he looked at himself in his mirror and saw that he looked to be seven or eight years old. It was at that moment that he realized what had happened. The stone hadn't made Mikey older, it had made Jon younger, so Mikey, still the same age, was his older brother.
"This isn't what I wanted," he said, hearing his voice the way it did a decade ago. He reached into his pocket, but the stone wasn't there. Where did it go? He looked around the room, thinking he might have dropped it, but it was nowhere to be seen. One thing that caught his eye, however, was that this wasn't his bedroom. Yes, it was the same room, but it was decorated in black. It looked like Zoe's room.
And as Jon was still looking around at the changed room, the bedroom door opened and someone walked in.