Learn about OS's as well as networking you will live in a shell most of the time, so BASH and Powershell or cmd will be your goto. Most of hacking is networking and OS's be it a bad config or sloppy admins who don't patch, either way you need to be the jack of all trades. Learn some coding, basically nothing at some point should be smoke and mirrors and a mixture of magic.
At some point you will want to dive deeper so books:
Penetration Testing: A Hands-On Introduction to Hacking
Violent Python: A Cookbook for Hackers, Forensic Analysts, Penetration Testers and Security Engineers
The Web Application Hacker's Handbook: Finding and Exploiting Security Flaws
The Shellcoder's Handbook: Discovering and Exploiting Security Holes
Cybrary.it is also an option, another important resource is
https://samsclass.info/ I also strongly suggest you get comfortable with coding as noted Python and C/CPP also if you are wanting to learn Web Application pentesting consider learning html/javascript/xml/php/sql.
