That's so obviously false that I doubt she's saying it. I suspect it's more like: these qualities tend to come up in childhood, so if we want to see more of them, that's where we should focus.
Everything about your comment ("I figured out HTML on my own") makes me bet you that had these qualities in spades as a kid long before you had a computer. All this existed before computers, after all. I remember Jerry Weinberg saying that he knew he wanted to devote his life to computers from the day Time Magazine ran a futuristic cover story about them in the late 1930s. Another farm kid, as it happens. He went to college to study computers and found they didn't exist yet, so he majored in physics and bided his time until programming became a thing.
I wonder sometimes whether any of this is about childhood per se or the fact that children are more likely to do things out of play, to figure stuff out, see what will happen, and so on. If that's it, then we can dispose of the controversy by agreeing that people who come to programming purely as a career or (god forbid) for status will do worse not if they're too old, but if they're too uncurious.