You'll get better. If you're new to gaming in genreal, you have to remember that many of your opponents have many years of experience on you.
Some may even have a decade or two, so don't worry about it. You'll get better in time. Chances are, this isn't their first online game, so they've played enough games to have much needed experience.
It takes a long time.
If it makes you feel any better, I just got done playing two rounds Socom 1 on the PS2, and I was getting destroyed. Granted, I haven't played it in months, but I've put many hundreds of hours playing it in the past. You've just gotta get used to it. Eventually you'll get good enough reflexes in the game to start doing better. It's like anything else, you've just gotta practice, and that means playing it a lot.