In my opinion starting programming at a young age is almost orthogonal to being interested in HN links and discussions from a young age, mostly because kids have other interests than adults, even if they like programming.

I'm not saying that there aren't any children reading HN btw.

I'm fifteen and have been reading HN for more than a year now, and I would have to agree. The content on HN is interesting for those who intend to make a career out of technology, not necessarily those who program solely because it's fun.