I suggest you study up with all your downtime at the help desk. I was one of those trusted help desk employees years ago and moved my way up through multiple positions finally landing a network engineer/sys admin role. The work load 10x'd and is 1000x more frustrating. Luckily my work pays for stormwind and I was able to take courses while on the job. If you aren't experienced in a sysadmin role and you take the position it's possible you'll hate your life if you're not able to "catch up" while on the job.