Some people are born with confidence. Some poeple grow in confidence through achievements they make. Some people are confident because of praise. Some people learn to manifest inner confidence without knowing how they do it. Being confident on the soccer field or in life isn’t something you can learn to do overnight. However, it is something anyone can learn to get better at. If I didn’t describe you above don’t lose hope because there is another way.
Throughout my athletic career I learned that there are things in life that you can get good at without talent. You can spend extra hours in the gym, you can spend some extra time after training to work on your endurance, you can study film, you can eat healthy, you can find a wall and improve your foot-eye coordination, you can spend an hour before bed working on your mobility for injury prevention, you can do all these things without talent, all you need is a want. A strong enough want to not doubt your direction and sacrifice (which should be the first question you pose to yourself).
Here’s the point I would like to make, 99% of people on your team, in your job, at school won’t do the extra. It’s just the way things work, most people either quit, lose hope, or were given a path that was paved and didn’t switch over to their mountain bike when the asphalt turned to sand. How would you feel if before a school exam you studied for hours diligently, making notecards, going over past lectures, and your friend who is '“smarter” comes up to you and asks you a question you know like the back of your hand? This principle applies to every aspect of your life.
Garner confidence through knowing that you have done everything you can in order to be the best you can.
The rest are things you cannot control.