Since I have recently finished my first novel, it makes perfect sense that I should be able to answer this question without sounding precocious. (Did anyone else just sing super-cali-fragilistic-expialidocious? If so, you're welcome.)
What I can answer is how long it took ME to write The Senator's Youngest Daughter. Frankly, this it going to vary greatly depending on:
- How long your novel is. YA adults are going to be shorter than adult novels. Also, certain genres are expected to be longer. Sci-fi or fantasy, for example, require a lot of world-building description and therefore, the books tend to be longer. (I do not have any alien appearances to describe in this book.)
- How often and how much you write. If you are like one of my writing friends, you will write at least 600 words, five days a week before work. (Dedication!) If you are like me or my sister, you will write in thirty second increments whenever you can, interrupted by children and laundry and dishes and lunchtime and playtime and Seuss-reading, then for like three hours twice a month from 11 pm until 2 am until you accidentally whack your head on the keyboard and take that as a sign to bail and go to bed. (By the way, the next day when you re-read what you wrote, the last few sentences about enchilada pizza should be removed.)
- How much editing you do. Apparently, some people edit as they go. This is not me. I have no less then 29 versions of The Senator's Youngest Daughter. Changing little things and big things, polishing the writing, fixing inconsistencies... so much to be done. Then after your first person reads it (my husband, in my case), they'll give you a ton of new ideas, ask questions you hadn't thought of, and point out holes you thought you'd explained. So, more editing.
Back to the original question, though, I first started taking myself seriously (after a conversation over grilled chicken with aforementioned dedicated writing friend) and believing I could write something novel-length in May 2014. So, two years and three months for 94,710 words. That's my answer. 820 days. 19,680 hours. Hmm... doing the math, that means I wrote just under five words an hour on average. Although, I didn't account for sleeping or going to the bathroom or driving. (Ahh, that's the reason it took so long. Too much sleeping!)
Maybe my second novel won't take me as long? I'm currently about 3/4 of the way into my next project (which, in case you're curious, is unrelated to The Senator's Youngest Daughter; it's not a sequel or something), and I already know it's going to need extensive editing. I don't outline my writing explicitly, so there are a bunch of things that I've sort of "discovered" as I've gotten to know my characters, so they'll have to be seeded earlier in the story.
My writing style
+ my available time
+ extensive editing since I am a rookie
= 2 years, 3 months