Not to be rude, but I don't understand the point you're trying to reach. I'd certainly comment if you reworded your thread

I'm 38 years old and I can beat Ninja Gaiden, Contra and any other NES game via cart with no save states. I can also play online FPS like COD or Halo and dominate. So if there's a "prime"... it's certainly not before 40. Stop believing all the bullshit you hear. Video games are not like professional sports. 

I'm better in my 30s than I was as a kid. I'm much quicker in reaction times and able to access what's on screen better. My hand-eye coordination is the best it's ever been.

If you got the time, you got the spine.

I dont have that much of it anymore. However whatever. 90% of the time gaming is a disappointment these days anyway. So itsnt that heavy a loss.

All it takes is devotion and understanding. In lots of areas, not just gaming, I go back and understand things better that I didn't understand before. I often think "I was so dumb".

You can be better at games at a older age because your smarter now than when you where a kid... however :

https://www.ncbi.nlm.nih.gov/pubmed/8014399

"This study analyzed auditory reaction time (RT) data from 1,265 community-dwelling volunteers (833 males and 432 females) who ranged in age from 17 to 96. Cross-sectional analyses revealed slowing of simple (SRT) and relatively greater slowing of disjunctive (DRT; aka "go-no-go") reaction time across decades for both males and females. Repeated testing within participants (longitudinal analyses) over eight years showed consistent slowing and increased variability with age. Males were faster than females cross age groups, RT tasks, and visits. Beginning at about age 20, RTs increased at a rate of approximately 0.5 msec/yr for SRT and 1.6 msec/yr for DRT. Errors also increased, making unlikely a tradeoff of accuracy for faster responses."

You also notice this in sports. However because alot of these sports are high on techniques, it first starts becomeing noticeable when your like 30.

In Esports and especially really twitch reactionary ones, like counterstrike, age plays a huge part.