Good for you. Do it because you like to write, not because you want to become rich and famous. TRUE, there are some well known writers than have made a lot of money. There are also some well known rock bands that have made a lot of money. It's about the same thing.
If you look at almost all of the popular writers, they are generally old, and have spent many years writing before they became well-known. Did you know that over a million people a year write a book? After I'd written my first, I called Barnes & Noble. They nearly laughed at me. They probably have a few hundred writers on their shelves. Those writers were chosen out of the million + that wrote a book. Why would they choose you?
Personally, I'd done lots of ACADEMIC writing as a professional scientist. Selling those books was NOT my problem; I was asked to write them. I made ZERO from doing it, and I doubt that many copies sold. But again, the publisher came TO ME.
So write. And have fun writing. You'll learn a lot. But make a living from it? You'd better not count on that.