Big Sis Kim Kardashian Thinks Birthday Girl Kylie Jenner Has "Grown Up Way Too Fast"

Happy Birthday Kylie Jenner!

The daughter of Kris and Bruce Jenner, reality star power couple behind Keeping Up With the Kardashians, turns 15 August 10 and her sisters can't believe it.

OK! NEWS: OK! EXCLUSIVE: KENDALL & KYLIE OPEN UP IN INTERVIEW & PHOTOSHOOT

Older sis Kim blogged, "Happy 15th birthday to my stunning, silly, smart, talented, funny little sister, Kylie! I love you more than you know!! You are growing up waaayyy too fast for my liking, but what an amazing and beautiful young lady you have turned into. We are all so proud of you and I can’t wait to see what the future has in store."

OK! NEWS: OPRAH WINFREY MEETS THE KARDASHIAN KLAN: WHAT DID SHE THINK?

And Khloe tweeted. "How are you 15? There's no one like you in the world! Never change! I love you!"

No word on what the model's birthday plans are, but knowing the Kardashains, we're sure they'll celebrate in style.