6 years old is definitely ok for her to enjoy Monopoly. She might not understand the game, but they pick up so quick and there is so much going on, there will be one aspect she will slowly like. Mine like the hotels from the start......she obviously knew more then she was letting on! :)

I love Risk too, but that might take a while to learn if she is even keen.

P.S. Make sure to set aside 2-3 dedicated hours to play Monopoly, especially at the start as the going is slow. Good Luck!