How to test whether you really need a SLR, and where should photography start?

Recommend some books to read the New York Institute of Photography, New York Institute of Photography-Xu Edition and SLR Bible.

After all, you want to be a professional. Instead of buying an entry-level SLR, I suggest buying a second-hand mid-range SLR, buy a fixed-focus lens first, and then make a good start when you have money.

The New York Institute of Photography is not only about photography, but also about how to become a photographer. That's what you said. It's more thoughtful.