Welcome to OCDO!
There's lots of knowledgable people here who can help you out if you ever need advice on something
although, before driving your girlfriend even more crazy, I'd try to get her to start OCing or at least CCing if she's legally able to.
You probably either were so nervous you thought the employee was acting wierd or your just in an area that OC is not common. I was OCing once in a very small town (Alberton) in Montana, and someone pegged me as an outsider right away because i was packing, he said "this is a very gun friendly area, people just don't carry cause this is such a peaceful little town" sometimes people may seem to pay more attention because they don't see it every day.