I've looked up a couple of ways around this, but none have worked so far (example, using the command resetpassword while in recovery mode in terminal - it no longer allows you to select the root - it only shows the two Standard account - no way to create an admin. And no way to create a new admin user without an existing.

Any changes to the system or software installs I try to do that require admin approval, I have no way to grant it.

There is no admin account at all, which means I can't seemingly fix this problem because there is no admin I can log into. I am hoping someone might know how to fix this - after updating to High Sierra, the two admin accounts on this machine are all of a sudden standard accounts.