Disclaimer: won't call myself an WordPress expert.. ;-)
How many pages is the website?
If you have no experience whatsoever and are completely new to web technology, then I would consider hiring somebody if you want a professional result. Regardless whether you build your own site or use a CMS. As well as somebody to maintain your site/ CMS at a regular basis. This is if you want to things do right.
Another option is to delve into WordPress and learn how everything works. Get a web host which can help you solidly with installing WordPress, if needed. Find a free theme or buy one, and have it customized if you want to. This is not something which you can learn over night though.
If your website is small, and/ or you will not be using the features of WordPress or another CMS then it could be easier to have a simple website built. If your website grows and/ or the requirements change you can always switch to a CMS, such as WordPress.