You will always be a beginner and that is OK!
I notice a recurring subject in Reddit, people learning a language keep looking for more courses looking for the perfect understanding of Ruby, Rails, Python, Flask, Django and also JS, JQ, Node.js, Mongo DB and more.
Not only that, most don’t start coding their stuff because they are “not ready” and keep moving from one course to the other.
Let me tell you a BIG secret: “WE ARE ALL BEGINNERS, AND WE WILL ALWAYS BE BEGINNERS” you will never know how to do everything, you will always go back to a book, StackOverflow, YouTube, Github and many other places to understand something you no longer remember or you never learnt.
There is no perfect state of mind where you feel accomplished as a developer, and only there it is fine to start something on your own, don’t wait for this boost of confidence because it will never come.
Just start, break stuff, make as many mistakes as possible, you are not working in NASA if you screw a variable nobody will die, play, have fun and understand that you will continue learning for the rest of your life.
If you think I say this because I am an “Expert”, and it’s easy for me to mess with the newbies let me tell you that is nothing further from the truth, I started learning Python a month ago.