In Control Panel or in Settings go to users to check if you really have admin rights. It's easy to see.
Since you write you can't do anything except rebooting see if you can do it after booting into Safe Mode. It just might be that it doesn't do this check then.
https://win10tips.net/windows-10-safe-mode/ tells how to boot into safe mode. You might need the recovery drive you made (you made it, didn't you?) or a fresh bootable install disc or stick you have to make with the Windows Media Creation Tool on another PC.
Once you have that bootable disc or stick, you can use it to install the Creators Update and after that Windows won't ask this question again. Two things to do after installing:
1. Carefully check if the privacy settings are as you prefer.
2. Make that recovery drive.
I've been ignoring MS requests to update my security settings but now they say I must. It says "select security settings" but there's no "security settings" button. It looks like this but the big blue button isn't there:
I can't do anything except re-boot, then it comes back.
I guess the problem may be because it needs Admin rights, but it's my own computer and I have no other users so how can I not have Admin rights?