I want to invest more time into software development, but I’m not sure where to start any tips for a bigh school student?(9th grade)

I want to start learning more about what I should know for software development, but I'm not really sure how to even begin learning all that I need to know,I heard learning about coding is important to know, but I'm open to hear other options, any help would be much appreciated.

And if it means anything, I have Microsoft Office Word and Powerpoint certificates, I'm currently working on Microsoft Excel.