Learn how to use linux. Linux is an operating system framework (like Windows, OSX etc). Its free and what makes it really nice is that if you use Linux you get much greater control of what your computer can do. Learn to do as much using the command line as possible. The vast majority of hackers will use Linux – In Linux there are many operating systems (called distributions) – if you know how to use one, then its pretty straightforward in most instances to use others. One of them is called Kali Linux (https://www.kali.org/)- this is an operating system especially designed for ‘hacking’ and so has many of the tools hackers use preinstalled.
Maybe start with a distribution such as Ubuntu or Mint. They are pretty user friendly but possess the same back-end structure. Once you get on top of one of these, then maybe look at Kali, or something like Arch Linux.