[notakio]

My answer to your question of how to fill those knowledge gaps is "experience". Whether it's work experience, fiddling around at home experience, or classroom environment experience, this is going to be your best bet. The more hands-on experience you gain with a subject, the more the rest of the subject will make sense to you.

So, provided you've got free time, use it to gain experience. Pick a subject, and dive in. Spin up virtual machines, experiment, and learn from your successes and your mistakes. So long as you let your desire to learn guide you, you'll be able to pick up experience in any number of disciplines under the CS banner. And, the more you explore these various disciplines, the more likely you will discover one or two (or three or four) that you're really interested in, which you can then focus on and turn into a career.

In a way, your current mindset (of not thinking you know enough) is an advantage, motivationally. Every single thing you feel you don't know enough about is an opportunity to learn more about that thing. You're on the right track, plan-wise, whether you go full-time or part-time. Just spend the time you don't have to spend exchanging your labor for capital, building more intellectual capital for future you.