The creative aspects of being a professional author are perfect for INTPs, however an INFP would be better suited to creating emotionally rich prose and the dedication/perseverance required to see the project become a successfully published novel is the realm of the INTJ.
The talents of an ES are also highly important if one wishes to understand more than their own psychology and perspective, i.e. an ES can "discover" dozens of interesting characters by going to a local bar and seeking out interesting people, an IN however is so enrapt in hir own highly augmented perception of reality it can be difficult for others to relate to the fiction they write.
If you want to be a writer, I have three tips for you.
1. Carry a notepad wherever you go, because inspiration comes and goes like the wind.
2. Writing is a craft, study successful authors & literary theory to understand the how'n'why.
3. Unoriginal work is worthless, so write the story only you can write.
And lastly, good luck to you, not too much though, you're my competition