I have been taking a bit of a break from writing due to my crazy school schedule, but I looked back on many of my character sheets and realized that there were a lot of events that happened before the start of my book. Do I write a prequel at some point? Do I include all of those details within the book? It could probably be done given some editing, but I feel like there could be enough information to write an entire prequel story. Should I sprinkle them all in over the course of the novel? I'm only over three chapters in, so am I overreacting?
Some help would be appreciated.
I think a prequel would be a good idea. Maybe make the prequel the last book to get readers attention? It's your call.
If you could provide us with an example, that would be really helpful. My advice is that it really depends on what theme you're representing in the book–Since it seems that these are two separate adventures, they most likely have very different lessons attached to them. I personally am not a huge fan of prequels. If it was me deciding it, I would probably choose to just include backstory details in plot points where the characters are experiencing the most jarring parts of their arc and it's important to know where it's all coming from. In fact, a bit of mystery can actually make a story more compelling. Leave parts blank. Some of the best pieces of literature I have read are a lot like what you're saying, where a lot of the story actually happened before the beginning of the book. Ultimately you decide what it is you do, and you probably know what's best for your story. Just make sure to keep the writing you have already done somewhere safe!
Is it necessary to the story for these events to be explained in detail? Will they advance or add to your book in any way? If not, I'd recommend against writing a prequel unless it's something that you feel you'd really want to do and would be fun for you. Every book has events that happen before the story begins, and most of the time, they don't need to be elaborated on in a prequel if they can be explained in the first book. Try to fit as many past occurrences that are important for the story and reader's understanding into your current novel (how you reveal it is up to you). If you really think that you can't fit all of it in and really do need a prequel to enhance the book, then write one.
Also, if there are any details in your characters' pasts that don't matter to the story, then cut it. For example, nobody's going to want to know about, and they're especially not going to want a prequel including, that one year your protagonist's best friend worked at an awful retail store if it's not going to tell us more about that character or add to the scene/overall plot. Your readers don't have to know anything about random happenings in your characters' backstories if it won't matter in the story, so if you know that any events you're thinking of adding are redundant or worthless, I recommend against adding them.
Sorry if that was a bit long, but I hope I was able to help! Good luck with your novel.