Japan’s beloved Princess Aiko is often cheered like a pop star.

During a visit to Nagasaki with Emperor Naruhito and Empress Masako, the sound of her name being screamed by well-wishers along the roads overwhelmed the cheers for her parents.

As she turns 24 on Monday, her supporters want to change Japan’s male-only succession law, which prohibits Aiko, the emperor’s only child, from becoming monarch.

Along with frustration that the discussion on succession rules has stalled, there’s a sense of urgency. Japan’s shrinking monarchy is on the brink of extinction. Naruhito’s teenage nephew is the only eligible heir from the younger generation.