At what stage should I care about copyright and LTD?

I'm building my own wordpress website, I will be creating content and I'm not sure at what stage should I care about registering a company, and copyrighting my work?

If I add a footer pretending that I have LTD and copy rights reserved, without actually having these just yet - is this punishable in anyway? I think I should be focused on validating my product before going into these details, but still don't want someone to just steal my idea if it's not copyrighted yet.