She cannot wait till fifteen years old to have surgery if surgery is needed.
Her pediatrician should refer her to a pediatric orthopedist for evaluation if her bones and/or ligaments are out of alignment on physical examination.
I completely agree with not waiting until she is older, as I wrote. She should see a pediatrician for sure. Has she had the same doctor since she was born? May I ask whether it was this pediatrician who suggests you wait? In that case, I strongly recommend you get a second opinion or simply request a referral to a pediatric orthopedist for a second opinion.
If you live near a major children's hospital, that website will list general pediatricians in the area.