Check Remote Management Status via Terminal
You can tell if it's enabled by running launchctl list | grep '^\d.*RemoteDesktop.*'. That will output a line if there's an active process for the RemoteDesktop agent, and will output nothing if not. There's an active process for the agent whenever Remote Management is enabled, even if there's no active connection (unlike something like Screen Sharing, where the process is only active when there's a connection made).