I've got some good news and some bad news.
"The reason that you are nervous is because you really care."
Be aware that the more you care, the more nervous you are likely to get.
Everybody gets nervous. In fact, in sports, the term "choking "was invented, Choking basically means holding your breath when you strike a ball brought on by fear of failure. Choking is brought on by worrying about the consequences of winning and losing.
How do you not get nervous? Unfortunately, you will always feel nervous, but it is learning to focus on other things that allows you to play with more confidence.
You will notice that often, a great player pauses to take a deep breath before every point. This is to relax themselves and to help them to focus on what they need to do next. Most players create a place in their minds to go when they
get nervous. That is called, "the safe spot." The safe spot is that favorite place that you have gone to since you were a kid, that makes you relax. It could be your favorite place on the beach, it could be a room in your house. It really doesn't matter, as long as when you think of that place, you feel safe and calm.