There are essentially two types of writers: plotters and pantsers. Those who outline their plot beforehand, and those who write from the seat of their pants (AKA go in blind and make everything up as they go along). I said in the past that I was an outliner, but I now outline less than I used to. 

Outlines make it easier to know where you have to go in the plot. But one benefit of writing from the seat of your pants is that you are motivated to write more often and faster because you want to know what happens next. If the full story is thoroughly outlined, writing can become more of a tedious transcription-like process with little surprise for the writer. Less planning can create more fun, though I don’t know if I would recommend that approach to someone who doesn’t have sufficient writing experience.