I cannot change my kids apple id

I have my child on family sharing. I first quickly set her up with my email so she could get access - now she has her very own apple id ... I cannot change the email to her apple ID - I cannot remove or delete her account so we can start fresh - I cannot edit her information and it is my account, MY KID! What is happening?

How do I delete her from my family sharing plan? Why is this so difficult? Why does Apple have to make this process to hard?

I really hate this ... The web and smart phones and watches give to much access. I am trying to control this and Apple just cannot make anything easy or simple. The delete button is there and is grey'ed out.

PLEASE PLEASE PLEASE HELP