ASk Pedobear, he knows every game that will fit little girl's taste

My niece was quite infatuated with the creature creation process in spore when she was younger. She also enjoyed MSPaint quite a lot.

Any sonic game.

Toki Tori

I'm a fan of hidden objects games, and I think they could be good for a girl who's starting to read. Finding objects in the picture based on a word list is good for the vocabulary, and these games typically tell stories. Steam isn't the best place to buy them, but there are a few, such as Samantha Swift and the Hidden Roses of Athena.

http://store.steampowered.com/agecheck/app/19680/
:)

Psychonauts, Cave Story +, Sonic Generations and Secret of Monkey Island.

Huh he said LITTLE SISTER, not little girl, so it may as well be like he wrote, he being 47, and her 18 :O And HE MIGHT BE A PROFESSOR at college, so THERE!

Don't get girls girly games. Find her a nice, not gory game and that's it. No barbies or ponies or crap like that. It doesn't matter she's a girl, if the game is good (and for her age), she will enjoy it. You wouldn't consider if the game is "for boys" if you had a little brother, you'd just get him a good game and that's it.

Want to make her go crazy ? Super Meat Boy

Bastion, Braid, Trine

Alan wake or F3AR :D lol its a joke maybe CHIME OR CRITICAL MASS

Eets!

Buy NDS

I would suggest for a puzzle game± Portal 1 and 2, and you are lucky cause they are on sale this week so :)

Skyrim.

skyrim for real.creating female chars,my little sister loves it!

Terraria

Excellent for crafting and decorating your own world.

Men Of War series:)

PvZ is usually popular with kids.
My daughter loves Stacking but the puzzles might be too complicated.

Troll?

Skyrim
Or Lucid XD

The secret of the magic crystal! but this is for "machos".

Farming Simulator 2011

Max and the Magic marker