First off let me start by saying CONGRATULATIONS. Apparently your sup and management think you are a good worker and entrusted you with this task. I have been in this position and they only, in most cases, allow 10 to 15 minutes before start time for setup purposes. If you decide to do this please do yourself a favor; KEEP TRACK OF ALL TIME WORKED. The old adage comes to mind here, "An honest days work for an honest days pay." Write down all your times an keep a working log of total time for the days you work. Make sure they see you do this and they will not try to cheat you on time because they know your keeping track. Management should be able to adjust your time in the system so that when you clock in it will show your 15 minute early start time, or the start time OK k monitorywith the 15 minutes added.
Secondly, if you feel you can not do this, i.e. "I guess I could not get there until my actual start time", then don't agree or volunteer to do it. Manage many things try to my ugjijvb
Kkk really dislikes when someone agrees to something and then don't or can't follow through with agreed upon terms. It is up to you on if you want to do this, however if you feel you can't, then I wouldn't do it. You could always say to offer it to someone else that is as deserving or more deserving of the task. Makes you look really good that way and possible future supervisory material, if that is what you are shooting for.