Go and start using this language. You're ready. Even if you don't feel ready.
If you've read this much of the guide, you know more about how to learn Japanese than 99% of the world's population. But knowing how to do something is only part of this process. I know how to get in shape—I diet and exercise. But that won't make me get in shape. Going to the gym will get me in shape.
So go to your Japanese gym. Start speaking. Start doing those flashcards. Start owning on this language.