I began my computing life with DOS. Linux naturally attracted me due to the command prompt being the base.
But really, you may as well ask' "If one wants to seriously learn how to use a saw, where does one begin?"
We need goals here.
Fun? Install whatever Linux you can find on some spare hardware and play with it till it breaks.
I've been nearly 100% Linux since 2012, and I've tinkered since 2003,
AMA, but a tool is a tool. What is your goal that you think Linux will help you with? I may be able to help you with that.
