I think whether it's worth it depends on if she already has a handheld game system. Personally, I wouldn't think it was worth it (yet) for someone who has a DSi already. But for someone who doesn't and who wants to play Nintendo games (as opposed to the sorts of things available on the ipod), then the 3DS is great. It plays DS, DSi and 3DS games so for someone who hasn't played the older games there's a large backlog of games to choose from. I have one and like it, though I mostly play DS games on it.
Some people report headaches from the 3D effect. I get terrible headaches from all sorts of things so I was afraid I wouldn't be able to use the 3D but I've actually been able to use it quite a bit with no problems. It's not recommended that young children use the 3D much, and you can turn the 3D off if you don't want to use it.
There aren't a lot of 3DS games out yet, but that's changing. Basically, they released the system too early. There weren't many games ready when the system was first released, but good games are finally starting to come out now. Mario Kart, Super Mario 3D land, Luigi's Mansion 2, Animal Crossing 3DS, Kid Icarus and Kingdom Hearts 3D are a few major titles that have been announced and most of those will be coming out over the next few months. Nintendo has also announced a press conference to be held on Sept 13 which will apparently feature a major announcement about the 3DS.
