If she's already showing minimal signs of discomfort chances are she'll have worse problems in future. I'd sure consider the surgery--we had a springer done (both hips) at the age of 5 and although we never noticed that she was favoring anything or slow before, we sure did notice an freedom of movement and energy afterward that we didn't know was missing. Sometimes dogs don't let on how much discomfort they're in--especially young, exuberant ones.
Will she need both hips done or just the one? Ask the specialist lots of questions. You might want to ask them how long they think the implants would hold up--if they're going to wear out in, say, 6 years, you should probably wait. You don't want to have them wear out or break down during your dog's lifetime. Ask how early your dog can have the surgery--are the bones well-developed enough?
It's good that you've been offered the option so early--you can do a couple months of research before having to make a final decision.
If you have questions about the surgery and recovery itself, I may be able to help. I doubt the recuperation is much different now than it was when we had Priscilla done. That may also play a part in your decision--strictly limiting activity goes a far way in a good outcome. High-energy dogs are, understandably, more difficult to keep quiet.
"We are--each of us--dying; it's how we live in the meantime that makes the difference."
"It's not what you gather, but what you scatter that tells what kind of life you have lived!"
"Be kinder than necessary, for everyone you meet is fighting some kind of battle."