OK so I'm on chapter 43 of My novel. I added a new character and I want to change the ages of the main characters but I'm not finished with the novel yet. Should I keep writing or go back now and reread it and edit what I already wrote?
3mo This is my second draft. I rewrote the story so the subject is different but the genre is the same
I'd wait until you finish it, unless you have some burning opinions right now on what and where and how to edit it, in which case, you might wanna do it now, but not entirely, because you never know where this book might take you in the end. You might have to remove a lot of what you've originally written. Most books, at their end stages, retain in entirity maybe 20% of what was originally written...
Keep the most important information about your new characters written down somewhere, finish the draft of the story. Or if anything you can include the new character in from now, be sure to save this as a new document otherwise you'll forget. Another alternative is to rewrite chapters that you know you want your new character to appear.