Most such points of reference have been personal, principally times I have moved to a new place for a new university or job. The only real external event that has shaped my life was covid, and I refer to before 2020 as "before times". It coincided with a big change in life circumstances as well as the general disruption.
Quite a few people now have "pre-covid" as one of their reference points.
New Horizons probe mission has been "big" connector of life for me - I was still in high school when it launched (2006) and I was 3 (!!!) drops from University and 1 "finished" trade (log builder stuff) school later when first detailed images of Pluto arrived (2015).
Life after that has been much more clear as last "reachable" big mystery was solved - Pluto might not be planet but it has BIG heart
I'd say the eventual trip to Mars and finding out if there's life on any of Jupiter and Saturn's moons are pretty big reachable mysteries.