I believe the answer is yes.
202 donated brains from former football players were examined by the Boston University CTE center. Of those who played in the NFL 110/111 had criteria that the center believes to be diagnostic of CTE.
Finding CTE in former NFL players is not breaking news. The data from men who did not participate past the college level is in a way more striking and alarming. 48 out of 53 college players' brains demonstrated pathological finding of CTE and 27 of the 53 were classified as severe. There were 14 brains from men who only played high school football and of those 3 had changes said to be typical of CTE.
This , of course, does not speak to the issue of what is the prevalence of CTE in any group of players. The data here is highly selective The brains were donated typically by family members often in part because of concern that their family member has some mental or behavioral issue.This is numerator based statistics.
Data was not presented but it seems a reasonable assumption that the college players had experienced at least 8 years of football, i.e. high school and college and likely many also took part in Pop Warner of some such youth league .It is an open issue as to whether concussive and subconcussive head blows are more likely to cause to cause damage to the young brain.It was a reassuring false believe prevalent for many years that young kids just did not hit each other hard enough to cause concussions. Data from accelerometer measurements in helmets of youth league players have been shown to reach the range of impact forces seen in high school players so parents should have been disabused of that notion. but I doubt that most are.