May i know nintendog is it just can play as 1 dog holder? Because me n my gf also need to play.

Or any idea to delete the previous account ?

go to gamefaq to find out.

there are instructions for deleting the previous save game. alternatively, you can use the dog kennel to change which dogs you have active in the virtual home. when you are playing, you put your girlfriend's dog in the kennel, and vice versa when your girlfriend is playing.

Ok i will try XD.