Re: Should I quit?
Try CSGO, it just recently went Free to Play, and it's based off of the same game engine (Source) and make sure to set your FOV/Sensitivity to the same as this game and get some practice in.
Also what mouse are you using?
I would suggest getting a larger mousepad and trying 45cm/360 sensitivity for more accuracy.
I use 43cm/360/400dpi/1000hz polling rate and a SteelSeries Rival 310 mouse which has a "flawless" sensor.
Also check to make sure your mouse has a "flawless" sensor.
Another thing to do to practice aiming would be to go buy "AimHero" and "Kovaak's Aim Trainer" you can essentially set it up with Apex Legends or any popular FPS game's FOV and mouse settings to practice and it will be just like you are practicing in THAT game but in Aim Hero or Kovaak's.
So you can train your muscle memory and gain the benefit of having reflex training for flick shots and moving targets that aren't bot like or that don't just move side to side so you can actually practice tracking like you would need in the actual game.
I recently have been practicing with both Aim Hero and Kovaak's and have been purchasing new mice in my quest to increase my aiming accuracy. I went from a Razer Naga 2014 (Laser which is terrible for FPS because of built in acceleration) to the Logitech G502 (Loved it but too heavy even without the weights) to now the Rival 310 (Amazing mouse).
Also make sure your windows sensitivity is on the middle notch with acceleration disabled in the checkbox.
Those are just a few tips that should put you on the right path to getting kills, the rest is up to you! Best of luck.