We have 3 working labs, once you start to make training fun they learn very quickly and are super dogs. She is only 6 months so plenty of bounce in her, do you exercise her regularly, as it sounds to me that she may be bored. If you have a local stream/shallow river, try taking her into that and throw a toy in it, they love the water and also learn to retrieve. We have a 6 month old too, we kept her when our bitch had a litter.
As I said though, ours are all working dogs.