How do i say “no” ?

It’s 3 days before my wedding and a friend is dropping a bomb on me by asking if her 8 year old can come to get ready with all us adults.


I really just want some girl time in the morning with my mom, my mother in law and my best girlfriends.
I don’t know what to say or do. I see her side of things, but it’s also such a short notice that’s stressing me out.