The medium is so young, and so constantly evolving, that it's never too late to learn. I should know. I started at the Internet Tribune with no previous Web experience beyond after-hours surfing. Granted, knowing your way around some standard personal computer applications helps. While I was never part of the computer-assisted reporting priesthood, statistical stories have been one of my specialties from college days onward.
Curiosity helps, of course.
I got a glimpse of how HTML works in just by reading cached documents on my word processor to see the hypertext tags. Most pages I saw appeared to be derived from templates, the kind of boilerplate coding I used to do on the copy desk. Tenacity helps too. Turns out the digerati learn about cascading style sheets and such by staring at codes much the same way. The Web isn't the place for people who can't handle detail work.