[1] She stated that the song's title was inspired from a piece of dialogue spoken by the character Pepe: "When I was older I used to be a sailor, but I drowned in a storm.

[1][3][4] "When I Was Older was released for digital download and streaming through record label Sony Masterworks on January 9, 2019 in various countries.

[10][11][12] Derrick Rossignol of Uproxx said the song starts with "eerie" instrumentation consisting of "some bass and simple percussion".

[13] Patrick Hosken of MTV has compared "the gloomy, blippy" track to Lil Uzi Vert's "XO TOUR Llif3" (2017) and Radiohead's "Pyramid Song" (2001).

[2] Daniel Kreps of Rolling Stone noted that Eilish added sounds of "student protest shouts and Borras barking" and turned them into "rhythmic percussive elements to help drive the song".

[13] Tom Breihan of Stereogum stated that it is hard to see how "When I Was Older" has anything to do with Roma, although wrote its "themes of alienation might have some resonance" and called the track a "weirdly pretty song".

[16] Chris William of Variety praised the track for the lyrics, calling them "impressive" and also noted its "preternatural spookiness".

[17] Pitchfork editor Philip Sherburne described it as "gorgeous" and one of the soundtrack's best songs, noting that while its sound "couldn't be further from Mexico City of the 1970s", its thematic closeness to the film made it "a fitting contemporary extrapolation".