As to continue my anecdotal story, I could safely say that all of my interactions with computers up until the age of 14 were purely gaming with occasional drawing in ms paint. Even so, at the age of 14, I did manage to create a simple html web page, and install a php based web engine, those actions were barely conscious, just following some tutorials in my mother tongue. Only at the age of 17 I made some first real steps into using computer to compute, write first simple programs, and began to be able to understand how it actually works. I'm pretty sure, that all of the time I spent with computers before 14 contributed less than 0.1% into "getting into STEM" and that learning English, reading actual books, spending time in extracurricular classes did way, way more. But then again, that's just my personal experience. Though I believe, it's of many.