When being presented with the task of speaking a eulogy, the thought immediately is followed with an irrational fear of not been seen giving them a fit and proper speech. They have a lot of positive effect because something which is beautifully written and sensible expressed can actually have a soothing effect on the bereaving.
If loved ones are left to make the decisions then choices need to be made during an already stressful and exhausting period of time. The audience for your funeral speech couldn't be more sympathetic and welcoming, and your deep feelings for the person who died will make the eulogy powerful. Throughout your eulogy, you can take a moment to compose yourself, then carry on.
Just knowing you have a backup speaker will probably be all you need to stay calm. A marvelous life that is now celebrated forever. People often wonder whether it's proper to include humor in a eulogy.
Don't worry if it runs just a bit longer, take a deep breath and try to relax. You can include poems, quotations or passages from the Bible, when appropriate.