Where to start? (Tips?)

Hey, I'm currently 16 years old and I'm quite interested in taking Computer Science for my major in a few years, I have programmed very simple stuff In the past, but that's about it. Right now what I'm doing is exercising my ability in Codecademy and read the book "Code" by Charles Petzold to understand the basics first. Honestly, I'm still quite lost on where to start because I feel like I'm not doing enough, but I don't know what to do aswell, so can you guys give me some advice and tips for me?

Thanks In Advance