I normally recommend getting to the end – even if you change your mind about something big, just keep writing your book with the new stuff in mind (and, if you want, any scenes you need to insert earlier) and then sort it all out in the next draft. If you stop and go back to the beginning, often you can get stuck in a loop. Whereas when you finish, and really look at what you’ve made, it’s easier to figure out what you have to do next.
This idea – just keeping going until you finish the draft – is the break through realization I had while working on my current book on Storybird.
I’ve done well with short stories and had yet to finish a novel. Now I’m 2 chapters from finishing my first draft of a book because I finally realized I should just write until it’s done.