Diana, try not to stress out ! Meet your friend and enjoy yourself !! Don't worry about not looking like you did years ago. We really do all change. Your friend has probably changed too. That's why you shouldn't fret over how you'll look to them. What matters is renewing that friendship !!! When you see them, you're not even going to remember why you were worried about getting together. You'll just be having way too much fun.
And that's what you should be thinking about i.e. how much fun you're going to have with this person. No expectations. No judgments. No criticisms.
Just enjoy the moment. Have fun ! can't stress that enough.