This was somebody people loved, even if you didn't have much contact in recent years. You'll look at those people sitting there, and remember when you were samll. You'll see people cry, and maybe you'll sniffle a bit.

Nerves will actually help you not 'lose it', but it doesn't sound like you're in danger of a complete breakdown anyway. Don't be afraid of a tear or two, though. If you tear up, pause and let it go, close your eyes and breathe, then start again. Not one person who'll be hearing you will think less of you for it.