re: Shooter game practice?

This is your first shooter game and you only played 4 times I would expect you to get you arse handed to you. Dont be too discouraged. I've been playing FPS for 20 years and still get destroyed regularly because its not the only thing I play. You may want to try Battlefield 4. There are a lot of roles you can play and vehicles to use that support your team without having to always go toe to toe with other shooters. The new Call of Duty has a casual mode as well. Practice for a while, learn the maps and you will slowly improve.