Knees are complicated little joints. We've only got one pair and we underestimate their importance until they play up. Most people suffer knee pain in their lives and women tend to have more problems than men. Accurate Knee alignment and wearing well-fitting, well-designed shoes is the best way to avoid knee issues.
Also something to be aware of, If you have hyper extended knees, it means your knee joint has the flexibility to naturally over arch (think ostrich). Whether you're a dancer or not, this creates a beautiful aesthetic line of the leg, but it can also create problems. Having long, fully extended legs is great, but when the legs bear weight, soften the knees ever so slightly as not to lock the knees too far back. This keeps the standing leg straight, strong and supported.