If you feel like you have come a long way, you are right. There is always more to learn, however.
You will find that as you make your first app, you suddenly realize that there is a gap in your knowledge that needs to be filled to make some feature come to life. This is normal and guaranteed; don't let it put you off. Think of how to describe the problem and search for the solution on Google.
You might also find that specific classes in a project will grow beyond the practical and maintainable. This is a sign that there is a better way to structure things and there is probably a ready-made design pattern out there somewhere that will make your life easier.
To pre-empt this almost inevitability, why not study some patterns right away. One great source is Head First: Java Design Patterns, available from all good book stores.