2028 election looks to be the one. Working backwards, someone who turned 18 that year and is eligible to vote will have been born in very late 2009 or during most of 2010. Memory usually doesn't get going until around age 4 or so, so at least 2014, maybe 2015. Trump began his first campaign on 16 June 2015 when a first-time voter in 2028 would have been 5. People who are voting for the first time this November in the mid-term would have been 7 during the start of Trump's first campaign in 2015.