Ask HN: How do I learn information security?

I want to do information security since I'm little.

Years have passed and I graduated in engineering and computer science. I did CS research and am starting a new programme in CS.

I have done a few online challenges on websites like root-me.org, but I feel like I still lack knowledge to solve advanced problems.

How did you progress in information security? Did some classes / books / websites help you practically? Or should I directly go for an internship?