Werewolves aren't exactly Fairy Tales and neither is Frankenstein. Though I suppose there could be a connection between the wolf character(s) seen in Red Riding Hood and The Three Little Pigs and the Werewolf legend.
Yes, the folk tales, myth and legends are all pretty old. The Grimms' version of the stories only date back to the 1800s and are taken from earlier ones. Even the Grimms edited the stories to make them more child friendly. (Apparently there were complaints about the first edition).