My father recently died and my mother decided to speak at the funeral rather than have someone who knew him less do it. From that I would say that the most difficult bit is starting rather than keeping going. The first few sentences that she uttered were enormously emotional and shaky and I reckon most of us thought that she wouldn't make it through, but once she got over the beginning it seemed easier and she was able to get through.

Once you get going I would guess you will be ok so perhaps concentrate on the first few lines?

Good luck.