Can my MacBook Air Mac OS High Sierra Version 10.13.6 make a group facetime and how?

Important: To make and receive FaceTime calls with multiple people (Group FaceTime), you and the people you’re calling must be using the macOS Mojave 10.14.3 Supplemental Update or later, iOS 12.1.4 or later, or iPadOS. This feature may not be available in all countries or regions. See Make a Group FaceTime call on Mac and the Apple Support article About the security content of macOS Mojave 10.14.3 Supplemental Update.

https://support.apple.com/guide/facetime/facetime-requirements-on-mac-fctm35515/mac

Any luck?

Great news Rosemarie, take care! :)