Houston Astros manager A.J. Hinch (born May 15, 1974) is the first big-league manager to make the postseason who’s younger than I am.
This has actually been true since 2015 — the first year Hinch’s Astros made the playoffs — but I’m not sure I noticed it then.
Also, it’s unclear whether Bartolo Colon (born May 24, 1973), the last remaining big-league player who’s older than I am, will be back for another year. He says he wants to, but his performance in 2017 (7-14, 6.48 ERA) indicates otherwise.