Another vote for waiting and seeing how she does at Senior and Master. The Golden gene pool for good field dogs isn't that large and if she's healthy and talented you may regret spaying her now. It's not something you can undo! Plus if she's the dog in your avatar she looks quite pretty. I'd definitely get with your breeder or perhaps someone local who knows field golden bloodlines, talk to them about your dog and your plans for her before spaying her.