What's so scary? The worst that can happen is nobody uses it. Even in that case, you'll probably still learn something about programming, and might learn a bit about product development. If you put effort into it, it will be a good experience even if it doesn't take off. And if it does, so much the better.
The worst case scenario I keep imagining is getting a lot of bad press with key social media folks (blogs, twitterers, etc) and then having my chances for good press be dried up even after I fix the bugs.
Very few of the early adopters will dive deep enough to even find a bug before writing up their thoughts, and unless you do something like reveal credit card info to strangers getting a review that's actually damaging to your long-term potential is extremely rare. (And even then it's the internet, just get a new domain name and design and start over).
Much more likely is that you'll find some people who like it, maybe some who love it, and some who have yet to be convinced. If you're really lucky, they'll tell you how to convince them.
I meant the first comment to be encouraging btw, perhaps it didn't come off that way since it got downvoted.