I work in Web Dev now. Know how much I knew when I got my first job? Nothing. I have a friend who works in Aerospace. Know how much they knew? Nothing. I have another friend who started at an interior design firm that builds custom CAD software. Know how much they knew? Nothing.

Just follow your interests and don't stress about it. No reasonable employer is going to expect you to be a wiz in their specific field as a junior developer.