Even if you pass out, get tongue-tied, or say something stupid during your talk, they won't care. As long as they get something of value, they would be thankful. Then, remember all you need is two or three main points when preparing a speech. When I first began speaking in public during medical school, I wasn't aware of this simple principle. I wrongly believed that my audience wanted encyclopedic knowledge from me, which of course I didn't have. So I tried to research my topic thoroughly and deliver as much worldly wisdom as possible. Boy was that exhausting. It was also boring for my audience to suffer through. Later, when I began giving public seminars on how to cope with stress, I spent hours each week typing a 20-page script to read from, so I wouldn't forget any important tidbit. As time went on, I gradually learned that this degree of complexity wasn't needed. As a result, the length of my discussion notes gradually declined.