This doesn't fit my experience.

I mean, yes, this was me. I came in knowing most/all of this. I knew six (or more?) programming languages, had at least played with CVS/SVN, had installed Linux (read: fought with the Linux bootloader to get my AMD CPU to boot without crashing), had dipped my toe in a few open source communities.

But I was a tutor in college and I interacted with a bunch of people who didn't come in with any of this experience. Many of those people struggled, but I also know a bunch of people who came into CS knowing nothing, loved it, and went from zero-to-sixty faster than even the people who came in knowing a lot.

I'm still not sure I can identify what the ingredient was, but experience alone is not enough to explain it.