I'd written for years before that but had never sent anything to a publisher. My first novel took four years to write, but that doesn't say anything about the quality or the size of the novel. It was a learning piece, an apprentice book, because writing is not just a talent but a skill. It's something you have to learn and develop. It's a slow process.
Dreams are too flimsy and unstable for that.
Still, these were very strong dreams. Some dreams seem to stay in the mind for years with a clarity that approaches that of real life. Before that I had had almost no contact with Greenland. I knew something about it, because Greenland used to be a Danish colony. I grew up in a very poor part of Copenhagen where there were many Greenlanders.