You carefully make your wish. You may have the body of a 6 year old girl now, but you still have your old brains. Slowly you say,
"I wish that I would body swap with the kid named Jeff who is skating on my street that I am looking directly at right now, he will have my body and I will have his, and he won't remember being Jeff."
Suddenly you blink and find you have a face full of pavement. Apparently when you made the wish, you made Jeff crash. You slowly lift yourself up and take a look down. IT WORKED! You're not your old self, but oh well. This gives you a chance to relive your life again, and besides, Jeff had a pretty nice body, you could definitely learn to live his life.
Quickly trying to get away from that evil stone, you tell your friends to head over to your place (since you don't know where you live). You follow Mike, since he's on bike, he would get there first. You find that Jeff's house is only a few streets away from where you just came from. A relatively nice ranch style house. Jeff live's in the basement, and apparently Mike does too.
All three of you hang out for a few hours and you try to learn all you can about Jeff. You find out that Mike was adopted by your family after his parents were killed in a car wreck. There are two twin beds in your room, he uses the other one. Joe is a new kid in school, but you started hanging out together after you were all in the same Biology class last year.
You start to think that you could really enjoy this new life. It doesn't seem like school would be too tough. Your new parents are pretty nice, and you have some really cool friends to hang out with. Soon it's time for bed. Joe heads home and you and Mike get ready to go to sleep. School day tomorrow. He takes off his clothes down to his boxers and you get to see just how muscular he is. He is well built for a teenager. You wonder if you should have wished to been him instead. But you decide that you made a good choice, so you can live with it.
Soon you are both asleep, seems that Mike snores really loud, but you finally got to sleep anyway. One thing still bothers you though, what's going to happen to that stone? And what if the real Jeff learns how to use it? He doesn't remember the switch, but what if he makes a wish that messes up the whole world or something? You decide that tomorrow you are going to get the stone and destroy it.