Starting a novel can seem like a pretty daunting task--and it is. James Dashner, author of the best-selling Maze Runner series spent three years on the first book alone.
So let's break things down and make it seem a little less daunting, and little more manageable.
First off, let's clarify the word count:
Novel - over 40,000 words
Novella - 17,500 to 40,000 words
Novelette - 7,500 to 17,500 words
Short Story - under 7,500 words
Personally, I like to shoot for 50,000 for my novels.
Now for a little math. (thought you writers could escape the subject, didn't ya?)
Let's say you set a goal to write 1000 words a day. To achieve a 40,000 word novel, that would take a mere 40 days. Bring that goal up to 1500 and you'll have a draft done in a month.
But it doesn't have to be 1000. It could be 500, or even 100. (100 words a day will take 400 days to complete a novel)
And really, a year is quite realistic/reasonable. It usually takes me anywhere from 8-12 months to get a first draft completed.
Basically what it will always come down to is actually sitting down to WRITE. It doesn't have to be perfect--or even pretty. This is just a first draft. All you need to do is just GET IT OUT THERE. Write a little each day--or even every other day--and you'll get there.