In chess, there have now been four 12 year old grandmasters. ('Grandmaster' isn't an easy title to achieve, needing besides incredibly strong play, a high rating and doing very well in 3 tournaments with strong international opposition.) It's because of computers and the internet making every facet of chess learning/study incomparably faster than a few decades ago. And you can get a game in seconds anytime online..

There's no-one from before the chess + computer age on the list of the 36 players who've become Grandmasters before their 15th birthday : https://en.wikipedia.org/wiki/Chess_prodigy#List_of_youngest...