Kim isn't the first of the family to team with the youngest of the brood. Kylie previously collaborated with her sister Khloé back in November on a line of lipsticks with names like Damn Gina and Okurrr (a cute fuschia with a name that's awkward to say when people ask what you're wearing). Many young girls first start experimenting with cosmetics because they want to emulate their mothers or big sisters, so it makes sense that Kylie would bring the Kardashian gals into her company. They're probably her inspiration.
Source : http://www.glamour.com/story/kylie-jenner-cosmetics-kim-kardashian-collection