Honestly, continue building up your Python and Java skills. A little bit of Java is not enough. Don't rush your learning process. Learn at your own pace and make sure everything you learn can be applied to games. Once you know that, you can make anything(games being one example). Research new algorithm and learn to come up with your own algorithms. Same applies to data structures.
Remember this: a program = Data Structures + Algorithms.
Anything with menus will involve a solid fundamentals of GUI> Anything with animations (and moving still images) will involve logic, data structures and basic math.
Also don't skip chapters in the book. Programming in some way is cumulative. You can't really afford to do that especially if you are design software.
Again to repeat: just continue learning new skills and start applying them in Python and Java since you already familiar with it. You will find many answers throughout your programming journey.
This may seems like a lot for a beginner but as soon as you start applying them, it does not seem so. Just remember, don't give up. The result is priceless.