My first foray into programming was with powershell and it continues to be an enormous help for me in my career (caveat being that I have primarily worked on windows boxes). That being said, PowerShell is a weird language that has some unique syntax and operators that don't translate well to other languages. Python is weird too, but for other reasons (spacing!). I suspect you'll get more immediate benefit spending some time on Powershell since your working in an environment that fully supports the ps toolset.
As for learning, I read "PowerShell Toolmaking in a Month of Lunches" and found that helpful. However, I think your course of study is sufficient. Think the most return for the effort was just messing around in the powershell IDE on my local computer and working the Microsoft documentation.