We were at Walmart today and were looking for the shortest line. As we turned in towards one of the lines a girl (age 12ish) got there at the same time in front of us and was looking at the length of the line. She then motioned to her Mom to come over. I politely said "I'm sorry but we're already here". When she went back to her Mom the mother was saying loudly that I was mean and then complained for a while. If we get there at the same time and I have my cart there already, was I wrong to expect to check out next???? Or should I have waited for her Mom to come over from a few registers down and let them go first?