Personally, I like New Balance cross trainers. Make sure you get a well fitted shoe, that is important.
Diet wise - it's wonderful to eat as little processed stuff as you can (especially when all the other kids around you are eating crap - that doesn't make it easy, I know). Just be sure to continue to educate yourself about good eating habits, and what things will help you to reach specific goals as they come along, rather than thinking that all you need to do is eat a lot of fruits and veggies.
Never stop at the beginning basics - always keep advancing your knowledge as you go.