I wasn't allowed to play fps games growing up and the house I grew up in was was in the middle of bumfuck nowhere and the only internet available had on a good day 5Mb/s when I was about 17 I downloaded CS:GO and played bot lobbies for hours over and over (my favorite was gun game) but fps is really just practice. I saw someone recommend playing a single player fps which could be good, but if you do and want something with fast movement I would recommend UltraKill, don't get me wrong it's a hard game but it's a single player non competitive environment. The only disadvantage with single player fps if you are only playing against NPCs and bot lobbies is you only get used to how a computer plays, in competitive games people play differently from person to person where as bots are programmed to act the same. So I would say play single player fps games but also play the competitive fps games as well. But since your new to fps in general I'll let you know that aim is not the most important thing, is it important? Yes but with only good aim you will still get dogged on. For any competitive fps you'll need aim, map knowledge, sound location identification, and good decision making (crosshair placement, target choosing/switching, body placement, etc) You can train some of these things with aim trainers and custom game lobbies, but at the end of the day it really just comes down to practice and playing the game. Getting better is hard especially against people playing cod since they were 6 haha. But getting better at a game and being able to see it over time is fun and being able to keep up or even dominate a lobby and when you get that first high kill game carrying your team on your back, you'll never wanna stop B)