Haha I started my journey with Mint as well and still continue to use it for all my day to day stuff and "CTF" stuff. Digininja speaks much wisdom and I would say stick to mint as well but I can't pretend that I didn't like kali at the start. Kali was great because I could test all the different apps without worrying about compiling/configuring a hundred of them on mint. I don't really use kali anymore because it's not a great OS for your day to day stuff and there's only a handful of the "kali tools" that I regularly use so I just installed them on mint.
As for direction, there are plenty of good suggestions provided above and to add my five cents, I started out with simple CTF challenges on www.root-me.org and setting up a test network using my old computers and routers. The virtual environment is the simpler way to go if you don't want to mess around with cables, different PCs etc but I wanted to learn how to physically do this stuff myself. From there try hacking your wifi or some old vulnerable software you installed on one of the comps (google vulnerable LAMP server). Finally enough, hak5 sells some good gear as well if you have the spare coin. Not sure how it is for learning but I had fun playing with the bash bunny.
Anyway, learning is a personal journey so you will figure out what interests you and what doesn't as you go.
Good luck and see you around, amigo.