Skill compounds because every new ability gives future learning somewhere to attach.

Learning is not a pile that grows one item at a time. It behaves more like a structure, where each ability you already have becomes a hook that catches the next thing you meet. Someone who plays one instrument learns a second faster because the new material lands on ground that already knows what to do with it. The early stretch feels slow precisely because there is nothing yet for the material to hold onto.

So the useful question is not how fast you are learning, but whether you are building anything the next lesson can attach to. Go deep enough in one area to have real hooks, rather than sampling six things at the shallow end.