I honestly originally felt like Superman was in his mid 20's or something before they revealed he was 33.
Henry Cavill is 30. I'm sure they wanted Superman close in age to the actor playing him.
Ehhh.... Maybe. But in the same movie the 30-year-old Cavill plays an 18-year-old Clark in the tornado flashback and the 30+ year old Tom Welling played a 20-something Clark when the series ended. So the age of the actor shouldn't (and has never) have anything to do with the the age of the character. Unless Beverly Hills 90210 really was about a bunch of middle-aged high school students.
It strikes me as an instance of the symbolism writing the story over the story trying to make sense. Superman is 33 simply because he "needs to be" for the Jesus symbolism to fit that much more. Amy Adams is also in her late 30s so we can probably assume Lois Lane is too.
Which, again, feels... "odd." Now for "main stream"/career Superman being 33 I can see. But just starting out as Superman? Strikes me as old. He's really wandered around the planet for decades without ever learning he could fly?
Lois Lane has yet to find a boyfriend, husband or at least a serious relationship? It doesn't seem to "feel right", I guess, more so in Superman's case.