New to DAX world. Where to begin?

Hello Dyn user group,

I am really excited to start my journey in the DAX world. I am really new and i mean absolutely new. Where should I begin? I have plenty of C#, .Net experience as well as SSRS and SSAS with strong SQL server experience. I want to learn the DAX development and I have few questions.

Should I start with DAX 2009 or 2012? Why?

Where should I begin? Books or web trainings? I have the software tools ready to be installed.

I am certainly going to start with some online trainings and some books but not sure which one to start with.

I am looking for certification in 2009 Development or 2012 Development. Should I look for job first and then get the certification or certification will be my first step towards getting a job.

I already make 6 figures but I want to switch the career and ERP world is something I have not worked in before. So I think I will be busy few years in this new world.

Any other suggestions or any guidance. Please keep it flowing this way please.

Thanks a ton.