How an when to tell my children.

Carrie
I'm wondering how an wen to tell my children that there goin to have baby sibling/s. I have an early scan 2moz and if everything is ok which I think is ok. How an when do I tell them. Do I wait till my 12week or tell after 2morrows scan. I'm 7-8 weeks and my 3 girls at aged 6,4,2 birthday are al close soon so will be 7,5,3.
Thanks ❤️👶🏻