Start it anyway, and if you find that you get halfway through and you hate what you've done so far?
Start over!
I know that sounds like a terrible, daunting thing, but honestly, A) it's good practice to write and rewrite or to draw and redraw anyway, and B) sometimes you need to work through the bad stuff to figure out what the good stuff is. Or you have to write stuff you don't like to figure out how to avoid doing it in the future.
For example, I have some random story I've written three times! And I'll probably rewrite it again, because none of my past attempts ever quite lived up to how cool the idea is in my head. But I love the idea, and I'm not going to let failed past attempts taint my love for the idea, even if I didn't like what I created before.
So I say go for it, and if it doesn't turn out how you want, take a break from it for a while, and then come back and try again! And make sure to make note of what didn't work in the first attempt too, so that way, you can avoid those pitfalls in your next version.