It is okay to be a little bit scared. It heightens your awareness. The best in the world are a little bit scared. However, being a lot scared is not a good thing. When you feel a lot scared, you are usually not prepared. Start practicing with a purpose, apply pressure in your practice and develop a library of confidence and to draw upon when you feel uneasy.
Remember the next time you feel a little bit scared, it is a okay. Smile at the opportunity to get in the zone and perform your best. You can do it!