Ugh are you serious? Between it and the PSP from an unknowing eye it looks more like a pocket PC so you got that covered, but regardless there's games of all ages on the thing and it does more than games too like internet if you get that dsi as the browser is built in. PSP I have too, it doesn't look stupid or kiddie either, but it's more obvious it's a gaming device just a bit despite it does even more than the DS does stock.
I'm 33 have both, got a SP too I'll carry with me. I think you're safe. Gaming these days due to the Sony efforts of the last decade and Nintendo in the later half of this one ending this year mainstreamed the crap out of gaming. No one should feel stupid at any age carrying around either system and using it unless it's just at really rude and stupid times (dinner table, etc.) If you're outside resting, waiting, riding the train, stuck in traffic...whip it out.
