I also read the answers in INSIDER 80, so I will try not to think of that when I answer. Judging from the first time I saw The Phantom Menace, I would guess he was about 22. In episode IV I thought he was in his mid-sixties. For the prequels I minagined I would have him be about 30, or early thirties. Old enough to have some real experience and to look old enough to be a teacher. This is also assuming that Anakin is about the same age as Obi-Wan in the Phantom Menace; late teens to early twenties.

I once read that real human life-spans don't correspond to Star Wars. I think it was in an article inside a Insider a while back. Someone wrote in asking how Luke and Han and the rest can be so active for being so old. The guy wrote back something to the effect of look at Ben in episode IV....and then he said that the average life span for a human in Star Wars is between 150-175 years. I think they are just trying to make it possible to keep writing as many books as possible without losng believability