Kim Kardashian didn't make it to the first night of her daughter North West's pop-up event in Los Angeles ... but, don't think she doesn't care -- she's hitting night #2 instead.

Just a few moments ago, Kim posted the promotional pic for the event and announced she's "otw" -- on the way.

This is especially a big deal ... because Kim's beau Lewis Hamilton is competing down in Miami at this year's F1 Miami Grand Prix right now -- and, she's missing the quaifying stage.

Of course, kids come first -- and this is exact kind of motherly move we expect from KK. Plus, she can always fly out immediately after the event to see the actual race tomorrow.

As you know ... Kanye West and his better half, Bianca Censori, made a splash Friday night at the event -- showing up to support North and even wearing fake face piercings in solidarity.

North dropped her debut EP "N0rth4evr" on Friday ... and, collaborated with Complex on a two-day pop-up event -- where fans could enjoy the music and purchase merchandise.

According to Complex ... Ye took pictures and signed merchandise for fans along with his 12-year-old daughter whom he shares with Kim.

We expect much of the same from Mama Kardashian tonight!