as a born and bred hospitality worker and DH is as well.. to be honest i would have done the same as her if i was faced with someone bringing in food... for 1, I dont know who made it. 2, i have no idea how it was prepared(in what state your home kitchen is in) and 3 what was put in it..

it is about assessing your skills in the environment of their kitchen, as well as seeing how you work and communicate with those who already work their.
SO my tip for next time is go in confident with what you know! ask them questions about what you need to know but then just do what is asked and use you initiative especially in service times..

Good luck