Rara's always been able to sing like an adult. It's something she never really considered until ponies approached her after camp. Ponies who believe she has potential far beyond what her cutie mark tells her. Potential even to compete on Equestria's biggest stage...against Equestria's greatest talents.
WARNING: This fic assumes Rara's camp performance wasn't a voice acting error, and that she actually is one of those borderline creepy kids on TV who can sing in an adult voice.