I think it's common among puppies.. but not a good habit.
My dog did this for a long time.. Mordy can give you better advice I'm sure, but you can try the pills or powder, like Deter, on her food and it might work. Didn't for me though. Or you can try adding pineapple to her food, as this seemed to actually work for me. But in the end I had to just make her go while she was on a leash and I could clean it up before she had the chance to eat it..
Most puppies grow out of it..