It was hard enough for Dean's brain to get around the where of what she just said. It was damn near impossible for him to accept the when.
"Are you having a go at me?" he demanded. "'Cause that is not a smart thing to do right now." Dean was normally an easygoing guy, but the weeks of constant running were wearing his nerves thin. His hand tightened around the handle of his wand which he had pulled halfway out of his pocket. He knew there would be marks on his palm later from its spiral handle, but at that moment he didn't really care. Thinking rationally he reminded himself that cursing some random bird who was probably a muggle just because he was lost and confused wasn't a very Gryffindor thing to do, so he took a deep breath and stepped down.
"Dean Thomas," he replied, "and I'm really sorry, it's just that a few minutes ago I was in England in November '97." Granted, he didn't know a whole lot about magic, but even he was pretty sure it was impossible to accidentally apparate three decades and 3,000 miles off target.