Ask HN: When to make the startup public?

Hello,

I have a startup idea (a web service), which I consider profitable in general. I got basic concepts of "how to finance", "what to sell in detail" and "how to implement". So, I would consider it between the start and the middle of the seed stage.

But my greatest fears, beside the normal "this will fail"-fear, are to rush too early or too late to the market.

So my question is: When should I consider making the startup public?

I thought about just making the website and saying "coming soon", but in this case the "wow a new service hype" maybe gone before everything is ready.

Thanks for your advice.