Based on my experience with, and understanding of, Forteo I would say if you can afford it (as covered by your insurance or through the LillyCares program) I'd say consider yourself lucky to be offered that Forteo option and grab it while you can. (It's insanely expensive if you have to pay for it yourself.)
Forteo (teriparatide) is the only osteoporosis medication that works by stimulating the growth of NEW bone..

Most other osteoporosis medications work by slowing down the removal of OLD bone, rather than actively stimulating new bone formation.
This is not a GREAT method, because the body is generally removing that old bone because it is becoming weak... sort of chalky.
These that work that way include:

Bisphosphonates (e.g. alendronate, risedronate, ibandronate)
Denosumab
Estrogen/estrogen agonists
Calcitonin
Forteo is unique in that it increases osteoblast activity, leading to increased bone formation and improved bone quality and strength. This makes it effective for treating severe osteoporosis and reducing the risk of fractures, especially in high-risk patients.