My memory fails me
Don’t count on your poor overtaxed brains to remember anything for your ceremony; vows, speeches, words for the rings, or readings. You will spend the entire ceremony in fear of the minutes that you have to speak, and the addition of 200 or so of your closest friends will send even the most normally composed public speaker into waves of shock and nerves.
Your officiant can banish this worry for you. Ask them to either type the words you’ll speak onto a manageable size card, or recite them to you, a few words at a time, asking you to repeat them. This way, you’ll be as relaxed as possible.
The only things you should have to remember on your wedding day are the license, the rings, and your joy!