My friend has the SAME exact body as me, except I exercise everyday and eat healthy, she does nothing?

There are other factors to consider, Metabolic rate for one. I myself do not do that much exercise however I am very thin (I'm a guy, but I do eat healthily) and tall. I believe this is due to a very high metabolic rate meaning things I eat burn off quicker than other people. Even though you lead a healthy life you cannot change your metabolic rate. Plus don't worry. It doesn't sound like your very old and in the future eating a healthy diet will definitely aid your body, keep going I say! One thing's for sure, it's not going to be doing you bad. :)