All you have to do, to extend your trial period, is change number in TrialKey element in application.xml. This file is located in /Applications/Adobe Illustrator CC 2018/Support Files/AMT/AI/AMT. You can navigate there with this command:
cd /Applications/Adobe\ Illustrator\ */Support\ Files/AMT/AI/AMT
Then you have to open the file and edit it. You can use just nano editor in terminal.