lock this, chess.com
Good chess rating for a 12 year old on chess.com

Anything above the 800 average rating must be considered good.
Of course, there are 12 year old Grandmasters...
I don't think there are 12 year old grandmasters. I am pretty sure that Praggnanandhaa R is the youngest GM, coming to the title of GM at 16, which is the youngest a GM has ever been.
The youngest chess grandmaster is Abhimanyu Mishra, who achieved the title at the age of 12 years, 4 months, and 25 days.
just shut up