If you really want to learn invaluable cybersecurity skills, start playing wargames. I suggest (1) which is one of the best. If you manage to reach level 25 on your own, then you are elite and the knowledge you gained doing so is not only extremely valuable but something you can be proud of.
(Sidenote: I would hire anyone who reached vortex level 25 on the spot and pay him a six figure salary, without looking at any of his other qualifications/degrees/past experience)
Additionally, read every single phrack (2) magazine from the past 20 years and try to understand most of the material within.