You're never too old to be a gamer; the average gamer these days is a 3..1 year old man? 34?
There's a game out there for everyone, be it balls-to-the-wall action like Call of Duty or the sedate strategy of Civilisation.
As long as good games get made I have no plans to stop gaming until...
The PS4 is out at the end of November but if I were you I'd look for a cheap PS3 (be it new or used) not just for GTA V but for some of the other fantastic games that you've missed out on. The Last Of Us, the Bioshock games, the Uncharted series, Far Cry 3 and Heavy Rain to name but a few