Wow Raineypark, I never thought of that before. It's really an interesting theory, and food for thought. It certainly presents a more poignant and sympathetic take on Amanda's character than most fans seem to attribute to her.
While the idea of living your entire natural life span young and beautiful is appealing on a certain level, it might also be lonely, couldn't it? Watching other people around you age, and after a certain point you'd just be alone, what would that be like? You couldn't really couple with anyone for life, because you'd never be able to explain why you never age without them thinking you're nuts. No wonder she searched all those years for Quentin, knowing that he's one of the few who could understand.