I would definitely give her the supplements like glucosamine and such. I can say that at our first vet visit with Maggie, the vet said that her knees were a little loose but now at almost 2, she fine.
Hot Rod went from a grade 1 to a grade 3 in a matter of months and had surgery on his knee.
His knee is perfect now.
Maybe the jumping aggravated it (?) I wouldn't worry about it too much at this point just yet. My vet told me that all pups probably have a litte loose knee at some point. Just be careful and watch your babies...keep them from jumping and such. Try and get stairs or ramps to keep them from jumping, this may help and give them time to get a bit stronger. Best of luck.