Whitti this is a flawed poll in how you broke down the ages.
You should have used more standard demographics
5-12, some influence on parents but really no choice in what systems they have, relatively little knowledge of RPGs it is all new to them.
13-19 you start to have other issues (like the opposite sex) and start to have some purchasing power of your own as well as influence on system purchase and makeup. RPG experience starts to go up as does serious reading. (the second most important demo of this group)
20-24 independent and/or high consumers of little things, $3000 for a gaming computer seems entirely rational. RPG can become very serious and game life and social standing might be as important as real life?also most people are just starting to really start to think they can think. (the main demo of any game of this type ATM)
25-36 other issues become more important, family is usually an issue at this point and entertainment is just that?and escape, the wants and needs are viewed through the scope of if this is giving me any type of joy?these are the people with the most cares probably, but the least time, and are really just looking for a fun time sink.
37+ these are the looking at computers in a new light, or really old time computer users from when computers did little for gaming. (Monochrome days at best) this is the group that might invest more time in the game, for social things, but less time for adoration of peers, also this group is less likely to upgrade their computer every 2 years as some are. At best these would become big casual users but few from this demo would spend more then 15 hours a week at best. Also this group is least likely to want to deal with many problems.
We could split the high group more?but I don?t expect the MMOG world has reached the early baby boom generation much as of yet?it will, but I am not sure it has. The pre baby boomers I don?t see until some good and real gambling is introduced. But at that point the game would be more real world and less about high adventure.
These are just my opinions, but having 2-3 year spans till 20 and then a 10 year span tells you nothing.
Maturity levels are really bizarre in youth, and you gain nothing from 2-3 year gaps?you might as well have done 1 year gaps. The real demo of any entertainment post 5 years old is 15-45 and that is really where you can break up a lot.
As far as out target demographic?more then likely get older as we go since we as devs will age. But with an older Demo the longevity of the game is longer as well.