Because that wouldn't help the story line. In New Moon she first finds out about about the Werewolf's when hiking, and she had to tell charlie that 'working at a hiking store was bound to rub off sometime.' Also because it has to do with the Cullen's And Hunting/Hiking story. If she just got a at a Restaurant she wouldn't of had a reason to go hiking with Jacob and then by herself. So it might of been Better for her if it was in another story that didn't involve so much woods and stuff.