Why do you feel you need to 'find your niche?' Write about anything that appeals to you to write about - at least for a while longer. You will probably find that you'll come around to writing about your greatest interest or interests eventually. In the meantime, don't let the creative urge fade by not writing. Oh, yes, and write a little (or a lot) every day. At least until it become a habit.
If you're thinking about finding a niche where you can become a professional paid writer I have no advice to give. I've never earned a penny from writing though I've been at it for 50 years. But if you write because you feel impelled to, it's an innate urge and wants to 'out,' then write about...to reiterate...anything that appeals to you at the time.