There is no such thing as too early.
Ok, maybe if you don’t even have an idea yet. That might be too early.
But once you have the groundwork laid and a concrete idea? Go for it.
Start teasing your audience. Share images of your work space with vague captions about the newest project. Share an image of your pet “helping” you write your latest book. Share your favorite beverage that gets you in the mood to sit down and write. Bonus points if that photo is in front of your workspace with work in progress in the background.
Self-promotion is your biggest opportunity to gain new followers and sell more books. The earlier you start, the more people you can reach, the more pre-orders you will get.
Just don’t share any spoilers!