Counting change!!!!?

I'm 17 and i might get my first job at my local small grocery store and i would be working the cash register alot of the time. My problem is I'm pretty slow at counting change and I'm afraid i might be too slow or short change the customer/register, i don't work well under pressure but I'm working on that. I've been practicing counting change with my family but I'm not getting any better or faster. How many minutes is too long for the customer to wait while i count their change? I know i need to relax and just take it slow but it's kinda nerve wracking for me cause it would be my first job. How can i count their change faster, and be more accurate?

Counting change!!!!?
Relax! Cash Registers are electronic, so they tell you how much change to give back, and most people make visa purchases, so I wouldn't worry, if I were you. Just keep practicing counting back change, because you always want to make sure that you are getting your proper change back, yourself. Good luck!