https://www.polygon.com/2016/4/29/11539102/gaming-stats-2016-esa-essential-facts I mean I didn't really feel like digging for sources, this states the average to be 35. Obviously average and median are two different things but it's up there. Median has got to be somewhere in the late 20s to 30s somewhere.
You said the average gamer on this site in the mid 30s there is no way. I’d guess it’s prob early to mid 20s
https://www.telegraph.co.uk/technology/video-games/8564342/Average-video-gamer-is-37.html This states 37, no clue of the credibility of these or where they pull their date from and this was the fastest google search in history. Point is the gamer population is older