Little girl upset about her brother growing up

5-year-old Sadie with her little brother

5-year-old Sadie is dealing with some big questions at an early age. Check out the YouTube video above.  She heartbreakingly tells her family she doesn't want her little brother to grow up. 

"He's so cute!" she sobs, giving him a hug.

She's also thinking about just how short life is for all of us, big sisters included. "And I don't want to die when I'm a hundred!" she sobs.

Fortunately, her little brother's cuteness saves the day, as he gives her a little smile...and she can't help but give one right back.