The most important advice anyone ever gave me about HD is this: treat the dog, not the xray. Some dogs with horrible xrays actually lead active lives without any trouble until old age, when arthritis sets in. Other dogs with merely "marginal" xrays experience a lot of pain and need more intervention and management. It's so hard to predict which ones will be lame -- it's kind of like humans with degerative disc disease in their spines.
One thing you can do that will improve her odds is talk to the vet about getting her on Adequan therapy while she's young, and keep her on it. One of my friends' dogs has the worst hips her vet has ever seen, but they put this dog on Adequan when they adopted her at 3, and the dog is now 11 and doing pretty well, with some arthritis. She led an active, happy life and missed out on nothing. She's raw fed and has always been fit, and I think that probably also made a difference. Now that she's old, she's also getting acupuncture and aquatic physical therapy.
The reason to start Adequan early is that it will slow the degenerative process that leads to arthritis -- preserving cartilage and keeping joints lubricated. It's a 4 week loading dose of 2 shots per week, and then you should be able to maintain with one a month for a long time. It's a little expensive to do at the vet (maybe $50/shot depending on weight), but if you are able to do the injections yourself, you can save a lot of money (have the vet show you) -- I buy it for some of the rescue's dogs from Valleyvet.com with the vet's approval.