You also need to be aware of the type of scale used in manufacturing your instrument. There are many types of scales being used today in flute manufacturing and each affects different notes in different ways. In addition, if you own an older flute, the scale will be much different from the scales used in today's instruments. Remember that warm climate conditions will generally cause the pitch to rise so you will need to pull the headjoint out a little more than usual. Conversely, cold climate conditions will cause the pitch to fall so you will need to push the headjoint in a little more than usual.
Nerves can adversely affect pitch in several ways.
First, and most common is the lack of support that is a result of nerves. SomeTimes, Arial, Verdana, sans-serif focusing on the support in a performance can diminish the nerves. Secondly, be aware that nerves can make us close up the teeth, throat, and mouth so that the sound becomes thin and out of tune. Think of raising the soft palette as if you are starting a yawn and concentrate on a deep sound in the abdomen. Work to blend with the sounds that are around you and maintain a good supported tone for improved intonation.