How come I cannot reset my security questions?

Read these links please:

About Apple ID security questions

Click here --> https://support.apple.com/HT201363 to "Learn about Apple ID security questions, including how to set up or change your questions."

"If you forgot the answers to your Apple ID security questions" click here --> https://support.apple.com/HT201485

If you see the message "not sufficient information" here are two methods that are relatively similar for possibly recovering from "not sufficient information" by signing up for Two Factor Authentication at this stage. See these posts by Community Specialists:

click here --> https://discussions.apple.com/thread/252885215?answerId=255425124022#255425124022

and here --> https://discussions.apple.com/thread/253011979?answerId=255657543022#255657543022

Alternatively "Contact Apple for help with Apple ID account security", click here --> https://support.apple.com/HT204169