[FreakLegion]

Chess champions mostly haven't been young, but the dominant ones have often been dominant from the time they were young. Here's a list with ages: https://sportstar.thehindu.com/chess/world-chess-championshi...

The WCC is just a tournament though, and the winner isn't always the best player. In 1993 for example Kasparov split from FIDE, and nobody thinks of FIDE's champions as "real" until Kramnik brought the titles back together in 2006. Meanwhile Kasparov lost a match and his title to Kramnik in 2000, but remained the highest rated player until he retired. And Magnus outranked Anand for years before bothering to contest the championship.

The top three classical players today are in their 30s (with Arjun right there behind Fabiano and Hikaru). The most impressive to me though are Anand in his fifties and Aronian in his forties, in the 10th and 11th spots. And then of course there's speed chess, where the youngsters are barely competitive.