Try to keep in mind that this is a skill-based field, rather than a knowledge-based one. You can’t cram a certain amount of information into your brain and be ready. Invest your time and energy into doing steady, consistent work that builds on itself. Even if you are more interested in front end development, you’ll want to understand enough of the backend to be able to understand how the backend works and be able to create some full-stack apps. Especially as a self-taught new developer, being competent in all parts of a web application will mean a lot more doors will be open for you than otherwise.