# ls -lact --full-time /etc | tail -1 | awk '{print $6,$7}'
Note the above script has a hash, which mean the user is 'root'.
Zorin users may need to add 'sudo' at the start of the ls command:
$ sudo ls -lact --full-time /etc | tail -1 | awk '{print $6,$7}'
[Acknowledgements: How To Find Out Linux Operating System (OS) Installation Date And Time | 2DayGeek]