I'm 50 and plan to continue playing. As for receiving lip about playing, my response would be, "Who's yo daddy?"
Seriously, chronological age has nothing to do with your ability to play the game.
Your success in life or in this case the game, is about your attitude.
My youngest son (17) and I have played Air Warrior, EQ, UO, MOHAA, UT and several others over the past 10 years.
My first online MMORPG was a space based game offered by compuserve in the early to mid 80's.
Yes, those were the days, buying a 300 baud modem for 250.00 and paying 6.00 an hour to play......NOT ;)