Cubes have probably advanced quite a bit, and the advent of social media now means that the kids just copy each others tricks within minutes these days. My kid and his cubing friends went down towards a 10s average between the age 10 and 12, so in about two years of active cubing. But having the head of a 12yo kid (and amount of spare time) is almost cheating. You can learn anything in 2 years. I'm sure they could have learned Mandarin instead in that time. But I'll take it over being really good at Fortnite which was the other option.