Hello and welcome @Encounter 
Just to say firstly, if you’re having any issues with your free trial for any reason then you can contact customer support directly at team@discourse.org and they can help you out. 
But secondly, the hosted versions are a little different to the self-hosted ones, and if you’re on a hosted plan then the first admin doesn’t get to be extra special like the type Ondrej and Toddz are referring to.
(Though saying that, I’ve just managed to demote my main admin account with a test user admin on my self-hosted test site, so I may need to investigate what’s going on with that if I’m meant to be un-demotable )