So i just got a job as a part time deli clerk at a grocery and today was my first shift alone. It was a closing shift and i was scheduled from 4-8 and i was working by myself for the first time and didn't finish my duties by 8 like cleaning the slicers wrapping the foods etc... so i stayed up until 8:20 and wrapped up everything. On my way out my colleague who works in another department asks me if i'm new and she told me to always clock out on time regardless of the whether the job is done or not. She basically told me not to work for free for a single minute.
I'm 19 and this is my first ever job so i don't know what the standards and norms are. Is this normal thing to do? Would you just leave even if u didn't complete your tasks?