Advice for public speaking

I hate public speaking in general but when there are people that are in “higher ranks” at work are present I guess I get more nervous. For some reason my legs shake and it’s like my body is more nervous than in my mind if that makes any sense. Its only happened twice. I have a ceremony to go to tomorrow and I have to briefly introduce myself in front of 20 people. I am very worried about my legs shaking which would cause me to get even more nervous.