Sir, 11 and 12 year olds are NOT post pubescent. It’s right there in black and white. How about reading the article.
You are wrong.
Earlier Puberty: Age 9 or 10 for Average U.S. Boy
Growing Gap Between Physical, Mental/Emotional Maturity
By Daniel J. DeNoon
https://www.webmd.com/children/news/20121020/earlier-puberty-age-9-10-average-us-boy#1