Hi, Good evening,
This is a common experience when you put yourself in either unfamiliar or evaluative environment. If this is not present at other times, it could be simple anxiety. Apart from tremors people could also experience, racing heartbeats and sweating.
Relaxation techniques, breathing, distraction,some preparation for the activity will help.
Next Steps
if it still doesn't get better please meet psychiatrist.
Health Tips
avoid caffeine and anything that could get your heart racing before these activities.