Alice Cooper was 15 when he launched himself headfirst into fronting the British Invasion cover band that would later become the Alice Cooper Band, David Bowie was also 15 or 16 when he started his musical career, Angus Young was 18 when he became AC/DC's lead guitarist, and had been playing proficiently in various other Aussie pub rock groups since he was he 16, Zappa was 15, Robert Plant was 17, Dio was 15, Akira Takasaki was 14, Alvin Lee was 16, etc. So don't give me the "Won't somebody please just think of the children!?" horseshit when people have started at their (Babymetal's) age or even significantly younger and become some of the finest musicians to have walked the face of the Earth. If children have produced music like the music I've listed? They sure as shit can do better than Babymetal's trite.