How can I fix this error?

The error message is quite clear, isn't it? It even tells you exactly how to resolve it in almost all usual situations.

Sir, I am not able to update the java version

Then you are not able to use that version of the Android Gradle Plugin as it is a hard requirement of it.

yes Sir

I do mind, sorry. I'm sitting at work. And I'm anyway not too much into free personal private support

Oooo'

That only appears once you successfully synced the Gradle project (unless https://youtrack.jetbrains.com/issue/IDEA-354901/Option-to-configure-Gradle-JDK-without-linking-Gradle-project gets implemented). It might work if you set your

JAVA_HOME

variable to the appropriate Java. And to make sure, reboot your machine after you did, then try again. Or make sure the build is (temporarily) not applying the AGP, sync the project so that the option appears, change the Gradle JDK, then revert the changes and sync again.