Here are some thoughts to consider on reducing stage fright.
1. Be prepared. Chose a piece you know and love. Remember the other musicians present will remember how beautiful you played, not how difficult the piece was.
2. Go by the venue prior the event and check it out.
3. Bring your music.
4. Remember the stakes are low, really.
5. It will be good experience in preparation for a piano exam, if you are going down that road.
6. Leave critical family members at home.
7. When you arrive, speak with other musicians, who like you may be experiencing various levels of anxiety.