For a 6 or 7 year old, FFXIII might be a little on the complex side especially since the battle system requires quick strategic actions. If they were 9 or 10 then I'd say go for it. It is very different gameplay from pokemon. If they're smart kids then maybe they'll enjoy it, but 6 years old seems a little young. As far as content goes, its appropriate for all ages. The story might be a little hard to follow for kids that young also.

omg zombie thread

Yes!! Maybe they'll be able to reminisce on it when they're older and get filled with nostalgia! I was 7 when I got my N64 and my older brother wandered in and gave me Ocarina of Time, and yes I beat it at that age in case you're wondering.

They are young. And enjoy Pokemon.

No PS3. I would buy them a Wii.

I have problems with that kind of thinking.

When I started playing games, they were hard.  They weren't "kid friendly".  You had to sweat your way through the game, learn the patterns of the enemies and sometimes even the entire levels by heart to succeed...

There were no "easy modes", no casual games, and the games hardly ever took your hand through the levels.  You had to figure it all out by yourself...  
Yet kids still had a blast.

Heck, I was 9 when I first played Final Fantasy, in 1989.  I didn't understand everything that was going on, I learned a lot of the game's mechanics through trials and errors, but I was having a blast doing it.  Enough that it became my most beloved game franchise.  Before that, I was playing games like Maniac Mansion on the C64, hardly the most simple game for a non native english person...  

So yeah, kids can learn pretty fast.  As long as they understand the language, the game can and most likely will grow on them.  

I didnt mean from a difficulty standpoint. I strted on C64 at the age of 6. Had Nes at 7. 

I meant they already clearly  like Ninty games, a Wii seems are much more suited present at this time. ;)

Yeah, the OP mentions they play ONE Nintendo game on a handheld... Surely, they're hardcore Nintendo fans... ¬_¬

u should buy them a ps3 with ffxiii and other games like littlebigplanet, ratchet, modnation racers, etc. if ffxiii is too hard they will just beat it in a couple of years. I started playing ff at the age of 6, and i beat my first one at 9 or 10 years old, lol. I think that as long as u buy them other games ur ok. Buy them ffxiii

Littlebigplanet, ratchet and clank and modnations racers would suit them more to be honest. 

LOving Pokemon, makes more sense to go with games from that dev. Not switch to a company wo mostly do game which are currently  illegal for 6 to 7 year olds to play. Last time I checked FF13 was 16+  in my country. I have a 4 yar old. If someone bought my daughter a 16+ game at 6 Id punch them in th face and ask why I wasnt consulted first.