PHOENIX -

It's something most of us never want to do: grow up. If you're this adorable five-year-old named Sadie, it's terrifying and ADORABLE all at the same time.

In this video, uploaded by Alex Miller, Sadie is shown sobbing as she attempts to come to terms with the fact that her baby brother is going to grow up -- eventually. It would almost be sad, if it weren't for her giving her brother hugs and telling him how cute his little smiles are.

His response to all of this attention is indeed a little smile. Watch the video below or right here.