Joomla, as most of modern CMS-es are built to be easily managed by non-experts. That's fine, if you want to perform only basic things, and you have the time to do it yourself. You can change a flat tire for your car - but obviously you will prefer to ask a specialist to do the most tasks related with owning that car. And then we didn't spoken about a custom built one ;). Yes, the bottomline is, that you need someone with proper skills and experience to build a Joomla based website, to do some of associated maintenance ans security tasks to keep it in the top shape. And even if the hosting is pretty cheap these days, you should seriously consider to host your Joomla site with someone who can help you if things go awry, someone who speaks your language too - not only the hosting people's nerdy one.