This is definitely going to be a big step for you and it is rewarding. Learn the fundamentals and intermediate / advanced topics of C if that is your desired language. This forum has repacks made in mostly Java, and some made in C#. If you wish to learn these languages, I would definitely seek out a Murach book or go to udemy if you are a visual learner. Tim Buchalka teachs a great Java course and Danny Boehm has a great C# course. You will need to learn networking and database management. If these are easily achieved and you wish for more, try looking into a SDLC course (Systems Development Life Cycle) to learn the start to finish steps. This will not just assist you with starting a hobby, but it will also help you get into a career. Best of luck to you.