I’d always heard pay their age. I have a 12 year old who doesn’t babysit / has no interest in doing so. I recently hired a classmate of hers to help with my 8 year old’s birthday party as a “mother’s helper.” She was a great help and I paid her $12 / hr. Another day I hired her to come play with my yonger daughter while I was home so I could do some things and that worked well. I wouldn’t hire a 12 year old to truly babysit. (Oh, the 12 year old I hired passed babysitting course that included some basic skills and first aid.)

They need to be mothers helpers first. I'd pay $10 and they'd have to leave their phones on the kitchen counter or something. They play with the kids (and clean up after them) and keep them safe while I work/do housework but am at home.