I have always wanted to write a novel, but I don't know where to even start.
Well, a Novel is a relatively long work of narrative fiction, why don't you start with something shorter? 
Hmmm, that's a thought, but I really had my heart set on a novel, maybe romance.
 You mean a Novel about love and relationship?
Yes, exactly. Although, I'm not much of a romantic so maybe I should pick another genre. Any suggestions?
I like mistery.  Of course since Novels have been around for 2.000 years, there are all sort of genres.