The novelist Anne Simpson once gave me some good editing advice. Often the beginning (the first sentence, paragraph, chapter) is not really the beginning.
When we sit down to tell a story, it takes a while to warm up, to ease in. So then, in the edits, we must wade through and find the true beginning, the place where the story really starts, and lop off the rest.
I remember having this experience with an early draft of A Drawer Full of Guggums. Originally the story had an extra 500 words at the top. My main character got on a plane, flew half way around the world. Jet-lagged, she listened to her uncle snore in the next room. Bumbling around London, she struggled to find housing. And that was all great fun to write. It was quality time she and I spent together. But all along, I knew the story was about the main character and her quirky landlady. Which meant everything before their first meeting - all those hundreds of words - had to go.
Preludes and prologues, sometimes they are a red herring. Be brave.