Hi there, Bree_beee!
Thanks for reaching out to the Apple Support Communities! It sounds like you're having an issue with the passcode for your children's restrictions not working. Check out this article to Use parental controls on your child's iPhone, iPad, and iPod touch. Specifically:
"If you can't remember a restrictions passcode that you created on a previous version of iOS, or you forgot your Screen Time passcode, you need to erase your device, then set it up as new to remove the passcode. Restoring your device won't remove your old passcode."
Hope you find this information useful and take care!