One thing I never paid much attention to was character age. Basic D&D didn't pay any attention to it, and it was/is largely fluff in editions 2, 3.x, and 4. However, a quick look at the age tables in AD&D1, and you will see that many characters start out in the Mature age bracket, and thus have altered stats. The elven cleric's base age is five hundred years, and if he rolls high enough on his variable, he will end up in the third age bracket with even further modifications to his stats.
I tried to see a rhyme or reason in the age ranges (because I read far too much into this lovely game of ours), and the only thing I can guess is that elven society must move at a really slow pace. I also find it kind of amusing that magic-users and illusionists have to train until they are in their thirties just to be able to throw a single spell a day. Fighters, on the other hand, should just be thankful that they live in a society without a legal drinking age.