35 or over might be a bit strange as they would have started playing the game, which was meant for children (and today is meant for teenagers and children) when Pokemon was first made, when they were still adults.
Actually the way that Nintendo is really pushing its consoles as appliances, not just game devices, like with Wii Fit, and all the DS "Coach" games, I wouldn't be surprised if at least some adult, even middle aged and above, start to drift over to the real games and see what they're all about. I'm sure puzzle games could be excellent gateways into the rest, hahah.
Plus I know some gamers are getting their boyfriends or girlfriends to try things out, and in addition, I bet some parents would get a game for their kid, and maybe try it themselves.
But you have a point, and mainly because like some people have been saying, part of it's a generation thing. People who started playing when they were kids are the mostly likely ones to still be playing it as adults. I started the Christmas after Red and Blue came out in North America, and never really stopped, and now I'm 28, and really looking forward to Black and White!
I don't think an adult playing, say, Dragon Warrior Monsters would get a weird look. It's just that Pokemon has lots of kiddie baggage because of the TV show and the massive fad back around 1999-2000 and stuff.