Kim Kardashian's Sister Baby Is Now New Model: The baby of the Kardashian clan, Kylie Jenner, 12, is following in her big sisters foot steps by stepping in front of the lens to make a career.  Kylie is the youngest daughter of Kris Jenner, Kim Kardashian's mother. So far, the youngest K girl has stepped out in low-priced looks made by department store Sears, the Huffington Post reports. Big sister Khloe tweeted, "How fab does she look???"