I think I've had at least a thousand different business ideas in my lifetime so far. From simple products to complex businesses, I've thought of it all. Of course none of these ideas has come to fruition. And it's not because I'm lazy or unmotivated; it's because I know how hard it is to turn an idea into a business.
Being an entrepreneur is just plain hard work. There are no two ways about it. And anyone who tells you otherwise is probably selling something. There are ways to make it easier, of course; if you have good financial backing and a thoroughly researched business concept, for instance, you are far better off than the person who puts every last dime of savings into an idea that has not been researched one iota. But all in all, entrepreneurship is not easy.
But that's what makes people like you so extraordinary. Not only do you have the business idea, but you have the guts to make the idea a reality. And you're a teen to boot, with schoolwork and other responsibilities to make being an entrepreneur even harder than it already is.
So when I say that being an entrepreneur is hard work, I'm probably not telling you anything you don't already know. The thing is, you've decided that the hard work is worth it. And that's really the measure of whether you're really into something. If you're willing to put every last ounce of energy into a project--whether it's a start-up, a homework assignment, a friendship, anything--then you know it's really worth it.
After all, the things that are "worth it" in this life are rarely easily had. It's the things that involve blood, sweat and tears that you will remember and be truly grateful for.