She knew she hadn't misjudged where she had apparated to the moment the farmer's lantern ghosted across the house as he went back inside. She recalled that structure. She was able to see it from her backyard. The simple fact that the stone farmhouse was there and intact, instead of in ruins that hadn't been touched since the end of WWII was enough to convince Hermione that she was in the past. The man's clothing and slang terms only solidified her assumption. Not even George Weasley could have set up a prank this elaborate.