I have YouTube premium and haven't received my stadia invite, just wanting to see if everyone with YouTube premium will be getting the invite email?
http://9to5google.com/2020/04/03/stadia-trial-youtube-premium/
Seems like its for the UK and US regions first. If you live in one of them, there maybe other additional requirements to it or they simply haven't send out all the codes yet, or wait to not overload the datacentres. Could be many scenarios why you haven't recieved a code yet, honestly.
Hello @Therealmacoy,
as @ChronosP mention you before at moment is only available for US and UK.