agreed, there is nothing to support both theories, but Buffy tells Willow that it happened after she saw her first vampire and if she saw her first vampire during the facts in the comic then it never happened because there is nothing in the comics about her talking to her parents and obviously nothing about being sent to the clinic. But I'm just realizing now that just after that line there is the shot of a photo with a little Buffy and her parents, so it's possible that she was sent to the clinic long before the events of The Origin, when Buffy was just a child. After all it's not stated that the vampires she sees in the comics are her first, right? And this would explain better how it's possible that Joyce 'forgot'