Questions about ED Registrar job

I will be beginning training for an ED registrar position this week. I'm excited, but also nervous because I have no experience working in hospitals, most definitely an ER. I'm coming from working in the medical office at a residential behavioral health/D&A group home. All I will say is that it was 'interesting' and that I did deal with a lot of emergencies and had to do a lot of things that more qualified people should have been dealing with, like an LPN. But we didn't have a full-time nurse.
Anyway, I'm wondering first of all, is if you had any experience working in that area, did you enjoy it?
What kind of skills do you think you need to be able to do it effectively? I'm used to dealing with difficult people, that much I can say.
Is there a lot of math involved? I'm curious about that.
Does it keep you busy?
And lastly, what are the chances of moving up or into another position after doing registration for a few years? Particularly if you go back to school (for something other than nursing). I imagine it depends on the place of employment, but I figured I'd ask. This hospital is quite large with many locations.

Thanks!!!