@IronMace1990 I think Miku should be saying "Fans" not Fan. And I think she should also be saying "There's no one that falls into that category".
Anyway, I do find it interesting how the lack of magical girls is affecting their relationship. Rui is scared that since Miku will go back into becoming a magical girl, people will start to become fans of her, and he feels he alone should deserve to like him.
But Miku really is cute, even in her 30s. She'll be cute in Rui's eyes forever, even if not in other people's eyes.