Good luck, I got hitched on Thursday. I was also worried about the speech, last time I did public speaking I crumpled and went bright red, but I sailed through it.
It's been said already but everyone there is willing you to do well, it's your day and your are among family and friends which I found comforting. Plus, they will laugh at the smallest thing.
I printed on A5 card as I was worried I'd lose my place on a4. I read it over in my head a few times so I was familiar with it. I prepared it by googling some good example speeches and took the good ideas, tweaked them and added bits I wanted to say.
It's probably too late now but if you want to see mine to give you ideas then send me a trust.