This is highly dependent on your opportunity. As hard as it is to find qualified math and english teachers prior to the college level, think how hard it would be to find programming instruction.
That is to say, when I was in school before university there was no choice for studying programming.
There was but it was offered at a private religious school/camp, not via the public schools.
This was in a comprehensive i.e. a bog standard school and was in the middle i.e. vocational stream - possibly the approach of having specialisation at the middle and upper school works better for feeding children into UNI/Vocational track.
Right, so the bog standard schools you had the opportunity to attend offered something mine (and many others) do not. As someone who is always looking for good developers I certainly don't want to limit the number of people who can learn CS to only those who happened to live somewhere that offered programming at the public school level.