It is perfectly natural to feel nervous. We all feel nervous about something, sometime - particularly something new and unfamiliar.
I'm not at all nervous about the aeroplane or the engine - I have complete confidence in the theory and practice of flight. No, the thing that worries me is my c0cking something up!
As for the survival rate of engine failure - well, a wise pilot aims never to get into a situation where an engine failure would be non-survivable. Like not flying over built-up areas / mountains etc. in a single-engined aircraft.
SD