Hi, osteoporosis is rare in people your age, people with a history of anoxeria nervosa or on chronic steroids being exceptions. You would benefit from seeing a specialist, typically an endocrinologist (although you may need to find one specifically with an interest in bone health). The science of medications in osteoporosis is evolving. We are learning that people that we start on drugs like bisphosphonates shouldn't be on them indefinitely and rather should have periodic "bone holidays." Sufficient intake of calcium and vitamin D are clearly important for bone health. For premenstrual women, estrogen levels in the body also protect against bone loss. Weight-bearing exercise is also been shown to increase bone deposition.
Hope this is a start.