If you know little to nothing about server administration, then I definitely recommend getting a managed dedicated server. It's not just server monitoring (where they monitor your server's uptime, etc.), but also things like securing your server, configuring the software and firewall, etc. There's a lot of things that goes into a managing a server that it's not advised for a total newbie to just jump right in.
If you're new to server administration and want to learn how to do it, I still recommend using managed dedicated server so that you can practice your stuff without worrying about what to do should you mess things up (you'll be able to call the host for help). Just remember that if you do play around, make sure it's not on a server that's important (eg. your business site) since sometimes things do go wrong and, depending on the damage you caused, it's even possible that your server's data could not be restored. It's like learning to drive a car: you don't practice in a Lamborghini on a busy highway, you do it in a driving school track with a trainer sitting beside you.
