One year

(Sorry, I forgot about the wish only part.) Jon wondered what it was like to be a girl. But to really be one, he couldn't just be thinking of himself as a boy in disguise.... First, the easy part. "I wish to be female until I wish to change back." Second, the part that would show him what it was like. "I wish that for the next year the stone will vanish and neither Karyn nor I would remember the stone or my original sex, but after the year is over I'll have the stone back and we'll have our memories back."