I seriously doubt it because in the anime, when Felicita accesses Mondo's memories, Jolly looks about 16 or 17. If that's so, why do people think that Jolly is younger than Dante? I mean, just because Dante is bald, doesn't mean he's older than Jolly. And in Vascello Fantasma no Majutsushi, doesn't Jolly say something about him stopping his physical growth or something like that???