Also, if you're just starting fps games, don't expect fast results. You may need 1k hours to see some initial effect. Keep in mind that most fps veterans have up to 50k+ hours in (20 years of 7 hours a day)...
After that 1k hours you may already be able to compete with them.
For now, just look for advantages elsewhere. E.g., shooting some1 in the back gives you an enormous edge to win that fight (that's how I start most of my fights). You don't kill them - run away and look for a different fight (that is, if you care about not starting a new game yet). Learn to gather information without giving out too much, find good camping spots where you can get action fast and still retain massive positioning advantage. Everyone plays a tactical game in BR's, but you have to rely much more on tactical wins if you feel your aim is not up to par with your opponents.