The best revision for the claim as a rebuttal to the counterclaim is:
Students usually study government and civics during the last two years of high school, so 16- and 17-years-olds find voting to be a way to engage with what they learn.
This statement directly addresses the counterclaim's concern about low voter turnout among young adults by suggesting that engaging in the voting process can reinforce their education in civics and government, potentially leading to better voting habits in the future.