This is the game that I got for my three girls when we bought their Nintendo DSi's. They all loved the game. I tried playing it to judge the difficulty level and found it to be fairly simple. My four year old was able to navigate it without any problems.
My 9yo daughter loves it!! She enjoys creating her own fairies. I think that's the best part of the game. It is a very easy game for her so really no challenge. But its a game that they can continue to play over and over again.