Ideally, you Will come into Linux system administration slowly and after having had plenty of opportunity to explore and use the system as an ordinary user. When you do start the journey into administration you will hopefully have others around you who are already at various stages along the road ahead of you, and who will be able to guide your early steps. Or at least you will be one of a group of computing enthusiasts who want to make this journey together.
While this scenario will apply to many of you, there will still be many more without the necessary experience or assistance. If you really do find that you are initially on your own and that you have only limited experience of Linux, then this will be a slow and error prone business. In this position it is important not to become too frustrated or disheartened when things don't work right first time or when you don't immediately see how to do a particular thing despite having read the manual page a dozen times in order to wring the last drop of sense from it all
The first thing to remember about Linux, especially if you are running it on a PC and you have a DOS background, is that, despite all appearances, Linux is a big-machine operating system, even though you are running it on a small machine. You must cultivate big-machine operating system habits and mental attitudes if you are going to avoid many of the pitfalls which await to trap the unwary. The bottom line is that, even if it is not you, someone will need to be the system administrator for your system - while the amount of administrative effort can be minimal, it cannot be zero.
Even with all these warnings, the worst case scenario is that you manage to do something which trashes your installation. In this case, a very full Linux installation (about 150 Mb) from a very slow distribution medium (about 70 floppy disks) will still take no more than about two hours to complete in order to put you back in business.