Niece is interested in learning details about this area. Why, I do not know.😕
What types of reference material/classes should I try to expose her to.
Set up a meet with a technical school (not ITT Tech ripoffs :hmm🙂?
Online websites to visit?
Depends on where her current skill level is. Is she comfortable with any *nix OS or just windows? Learning your way around the command prompt is about as intro as you can get. Beyond that I can point in the direction of general DoD based guidelines and requirements I've worked with.