Kourtney Kardashian introduces new baby Penelope Scotland Disick

Kourtney Kardashian has stayed out of the spotlight since her daughter, Penelope Scotland Disick, was born on July 8 -- but now she's ready to show off the latest addition to the Kardashian-Jenner-Disick-Odom family.

Kardashian appears on the cover of the upcoming Us Weekly with new big brother Mason (2), and a very sleepy Penelope -- and though dad Scott Disick isn't on the front page, he did participate in the interview within.

"Nothing could prepare me for how hard I fell in love with her," Kourtney says.

She also notes that Disick has been "stepping up" as a father -- after his struggle with adulthood was well-documented across several E! reality series -- but he still has yet to change a diaper.