When should I switch my German Shepherd puppy to adult dog food?

She is 60 lbs, 6 months old and very healthy, skinny and active. But, she wants to eat my adult German Shepherd's dinner? Although getting better, dinner time can be a bit of a circus. She eats 2 cups Nutro Large Breed Chicken & Rice dry with 1/2 small can of Pediree Puppy food, twice a day.