What do u think about losing weight with practicing DDR??

yes 12 lbs seems ok , and since if your a novice at the game you might want to go to an option i think its tutorial or lesson in the game and they teach you the basic then by month 2, move up a diffiult level since your body will get used to month 1 it will be more challenge by month 2 because the songs will be more harder and make you sweat more, then by month 3 move to more harder levels, this change will make you lose weight as well as eating healthy, and so your body won't hit a plateau. also you could do some ab/core moves you can do after you finish ddring.