Emily,
Don't defeat yourself with negative thoughts if you get this job. Be as conscientious as you can be. Places like this see people who are slower doing the job all the time. It makes a big difference to them if you are conscientious. If they have a different employee who is slow because of a crappy attitude, it is completely different. Do what they ask to the best of your ability. Be pleasant, smile at customers, do everything you can to create that spot for yourself. Don't give in to negative thoughts. Say to yourself, "I can handle this. I will handle this!"
Sorry, I have no response from my 'friend.' I was disappointed that I couldn't get that information for you. Hope you don't think I let you down.
Moni