There are a few things to consider to understand why Google Analytics is not showing any data under your website’s Demographics overview.
First thing first:
Please verify that your code is correctly implemented. Google Analytics states that it is ‘Receiving Data’ under the Admin’s Property tab.
If your Analytics code is working and implemented correctly, you should check if those are the issues you are facing.
Second Possibility:
You may have significantly less traffic, which Analytics doesn’t have sufficient data to show you.
Another thing is that.
Probably, Google needs sign-in search users to their website to gather & guess their age & gender through their profile & to show it in the demographics overview tab.
So the right thing is to consider giving & designing the right content for your website to maximise web traffic to your website through Google searches with the right tactics of Search Engine Optimisation, i.e. SEO
Best Luck…!!!
Hope it helps,
Further Reading:
Thanks & Regards
Mandar Apte