Can't Wait

During our reading lesson yesterday, the story talked about how a girl was so excited to go on a trip. At the end of the story, she said "I just can't wait." After we read the story, I was asking questions to check their understanding. I asked, "Did she leave yet?" One boy raised his hand and said, "Ms. F, it is obvious that she got on the train already because it says she can't wait. She actually can't wait, so she has to have gotten on the train." I thought the expression "I can't wait," meaning I'm excited, was so totally common....guess not