i have met many players on this site who have just recently started learning chess about a year ago or so and are already almost masters, when i ask them what is their secret they claim to have lots of time and use it memorizing lines and doing puzzles that are increasingly harder. so this shows that it is not necessary to start at a young age. however starting at a young age increases your chance of having extra free time, and it increases your chance of learning to love it from the start and not have a heart full of doubt. so at an older age you can still master it if you apply the same passion and don't doubt. The polgar sisters were actually an experiment by their father. His experiment was to prove that genius was not a matter of being 'born with it' but a matter of developing it by applying a passion. THE TRUE POLGAR KEY TO MASTERY IS PASSION AND DEDICATION AND WORK!!
Master after just 1 year?! That's funny.
Blah blah blah, stop trying to twist other peoples words in an attempt to appear superior to someone else on a forum. It's lame.
Doesn't the story go that their father wanted to see if chess masters could be "made" provided that they started at an early age with appropriate training. His conclusion was that yes chess masters can be "made".
So far this has been proven time and time again by juniors who have no inherent talent for the game that then receive training and later become FMs, IMs, and occasionally GMs.