I have a great idea for an app?

Alright so recently I came up with a great idea for an iPhone app. It would be a pretty simple and straightforward app that would be entertaining while promoting healthy eating (which hopefully would help fight the weight/obesity problem in America while entertaining the user and being enjoyable). It seems like it would be successful because it targets a large audience (any age, anyone trying to eat healthier) and it would be engaging and easy to use.

The problem is I'm a 17 year old girl lacking not only the assets to fund an app but also any knowledge of how to create an app myself/sell the idea to someone who could. My question is should I attempt to create the app myself and do all the coding (I'm very intelligent, especially with math and science and got a 34 on my ACT) or is there a way I can sell my idea and still got profit from it/not scammed and have my idea stolen? I would want to have the app available for free but then add ads as popularity increased to profit from the app. What should I do?

P.S. I know this may seem silly and stupid since I'm young and over 500 apps gets rejected from the App Store every day, but I'm really convinced my idea could be profitable and helpful.

Hire a programmer. If there's a programming teacher at your school, they might be able to help. Don't try to sell your idea. You have no idea how much it might be worth and you will most likely be scammed in the process.

Everyone thinks they have an idea, unless you can actually create it then its meaningless.