Whenever making a wish, you should be careful about what you actually wish for. You can be easily put into frozen state for(ever) as long as you want, provided you would like to pay for it. The longer you stay, the better chance you would be revived (though you will get the promise and insurance now). Now, are you willing to really do that? You simply wished for being kept alive to reach your 800 birthday, assuming, I assume, you can live the way you live now. That assumption, if not stated in your wish, won't be full-filled, and you will be screwed. :)