Is reading the opera synopsis beforehand a sensible way to enjoy my first performance?

My friend closed the programme while I was reading the second-act summary. 'You'll spoil it. Just let it happen,' she said.

This will be my first opera. I don't know the story, and I like having some idea of who the characters are before several names and relationships arrive at once. She has seen this work twice, though she says she went in without preparation the first time.

I don't need her to explain every scene. I wanted to read the programme's short account myself. She thinks knowing the ending will take away the experience I've paid for, while I'm worried that spending the first act trying to identify everyone will do that.

How do I choose the amount of preparation that suits me without turning the evening into an argument about the correct way to discover an unfamiliar art form?