How can a 12 yr old be a GM while an mature adult cannot even reach 1600

Talent vs no talent. Money spent on education vs self taught. There are many reasons.

You had a life and became a normal person. That kid's whole life is Chess, so that's what he'll know from now on, and not much else. He will get to travel all over the world, which may only be small compensation. His childhood was spent in intense study for years, with, possibly, overbearing parents. He may be able to make a living, but he will have no backup skills in another field and he'll likely end up a coach to make money to live on. He could end up busking Chess at Cambridge. You have a family and a career and you probably know many different things about many different fields. There are always trade offs in life.

I am 12 and 1300+ blitz 1500+ rapid 1700- bullet. I also teach and lead chess club at my school!

That is only a handful few compared to the thousands or even millions of players who are struggling to even break the 1000 rating.

I won't say that it's a very fair comparison as the spotlight is usually cast on players who achieve something different from the rest. In reality, pick a random 12 year old kid and he/she is most likely not a chess GM (or even a chess player).

In other words, it's perfectly normal for a mature adult to face difficulty in conquering the 1600 barrier.

Chess is a skill.

Do you think just because you fought for your country and been all over the world you can fix a car engine? Or do gymnastics? Or sculpt a statue... of course not. Those things take years of practice, no one can do them automatically.

A 14 year old could easily have 8 years of practice... and that's 8 years of having no expenses, no worries, nothing. Parents cook them food and take them to tournaments... and if the kid is good, then some of those tournamaent are high pressure, such as winning best of their age for their country or the world. So 8 years of coaching and experience in high pressure games... what do you have that compares to that? You know how the horsey moves? Oh, maybe you watched a video on youtube? Don't make me laugh

All I'm saying is I should have the capacity to play well as much as a 12 yr old with my experience of playing the game longer than the kids entire life.

That 12 year old you're talking about has played and studied chess 6-8 hours a day, every day, for 6 years. Analyzed his (her) own games and tried to learn from every loss.

Have you?

The child has bigger brain and healthier body and fewer things to worry about compared to a grownup whose brain cells have died due to excessive alcohol or minor strokes and who has to take care of an entire family

Age, education, knowledge and IQ don't necessarily translate into chess ability.

I very much doubt that even if I spent 8 hours a day playing chess, and did so for 8 years, I'd be able to be a GM or anywhere close. Yet many others could.

He started learning young iguess

lt's the same reason why I still can remember all my girlfriends phone numbers, addresses, family names, middle names when I was 12 including entire rosters of teams, world series, shows, jingles, super bowls etc... But, I can't hardly remember the names of all the beautiful babes I banged in the past 3 years. The young brain is a high-capacity accurate recording machine. Memories before age 25 will crush those past age 25.

Its simple. Pros at skilled sports usually if not always start before 18 but definitely start before 25.

Same reason a 9 year old maths prodigy can do calculus and solve complex equations that some adults can't understand. Reasons for this? may be one or more of these: High IQ, Started learning chess at a very young age (like 3), high problem solving ability, repetition and hard work.

Why can all 12 years old chinese kids speak chinese fluently and a foreign adult would never be able to do so?

The 12-year-old in question is better than the adult and possesses enough talent to be worthy of the Grandmaster title.

But two equally talented persons, starting playing chess at diferent ages, would achieve different ELO ratings.

Yes, and this has to do with innate IQ and fluid intelligence.

IF you did that (practiced chess for 6-8 hours a day) when you were 5 years old, studied chess books, practiced and learned legendary grandmaster games, play in a chess clubs, practiced complex positional middle games you would probably become a grandmaster or at least master (2000) with persistence. That was the case for Hikaru and some other grandmasters. A man tested this out on his two daughters who had IQ's of about 90. He was good at chess but wanted to show that with practice anyone can become a chess expert and that it was not limited to only a gifted few. One became an international master and the other a grandmaster. The female grandmaster has actually defeated magnus Carlsen before in a park blitz chess game (not competitive, just for fun). It is on YouTube: https://youtu.be/hvbZCRid5CY

However, once in a while there are chess prodigies like Bobby Fischer, Levon Aronian, Mikhal Tal, Magnus Carlsen. Magnus raised his rating from 907 to 2000+ in the span of 2 years after playing competitive classical chess for the first time (when he was about 10 years old). His rating climbing up to 2800 when he was just 18 years of age.

Life is like chess to me that is why I can't accept that a 6 yr old be better than me. Forget the 12yo GM