I'm 25 years old. I feel a LOT younger, not in terms of maturity(I've always felt older than most of my peers) but more in terms of physical stamina and emotional and mental discipline.
But am I better than I was when I was 17? On MMORPG's and so on, probably not, in large part because of the amount of time I was willing to sacrifice back then.
On more reflex-dependent games, in some ways yes and no. My situational awareness and gaming intelligence is through the roof compared to back then and I was even back then pretty good at stuff like that, and I find that aim is kind of overrated anyway compared to gaming intelligence/positioning, but when I have to aim, I do very well anyway.
The only thing I've gotten "worse" at is doing something I don't enjoy.
Basically, grinding. This is part of the reason why I don't play MMORPG's that much. Even on FPS shooters, if there are too many level-ups/unlocks before you close the gap between those who are new and those who are not, I might be bored.
I just feel like a game should be like Counter-Strike. Everyone starts basically equal and the only differentiator should be the skill level.
But whenever I play a new game, like Titanfall beta last time, I pick it up really fast and do quite well. I was beating people on level 14 on a regular basis in my first 2-3 online matches on Titanfall.
As an old Freelancer diehard, I'm also massively looking forward to Star Citizen.
I guess age 25 isn't that old, in comparison to people over the age of 40.
I also think that games have actually become a bit slower. Even CoD isn't nearly as fast as Quake 3 or Unreal Tournament were. Those were really Twitch games.
I also become really, really good at Tribes: Ascend which came out like 2 years ago or so, despite never having played any previous games and that game is a lot faster than CoD and also has a lot more tactical elements to it, as well as a much higher skillcap due to the enormous amounts of movements you can do.
But yeah, MMORPG and RTS games are still fun as well and not an issue to get good at. Too bad that both genres, especially RTS, have seen a decline in the number of games coming out. I grew up on RTS before I discovered FPS, especially AoE.