My cite does not agree with your assertion. I suspect that has to do more with how the demographic is defined than with the accuracy of either of our data.
In either case, it’s clear that voter participation increases with age.
It really doesn’t. Check the actual numbers in the appendix 1. Now mind you your cite is looking at the youngest subgroup of 18 to 24 only while the one I cited was 18 to 29, but not much different.
Average turnout 18-24 year olds presidential elections last 4 cycles(2004-2016):40.9
For the 4 cycles before that (1988-2000): 35.9.
Mind you going back farther not as bad, and 1972 was an outlier year with especially good youngest voter turnout: 49.6. Above even Obama in '08. Of course that excited youth turnout was what lead to the overwhelming D win that year … by McGovern against Nixon … nevermind.