A colleague of mine did her MSc thesis looking at what criteria dance schools used to assess a girl's readiness to begin pointe work. The results were pretty depressing. Nearly every school used age (usually 12) as the determining factor. Some, like mine, used level. Which worked out about the same as age. Almost none even considered strength or physiology.
While talking to a friend about this today she mentioned another friend of hers who had trained in Irish dance, something I know very little about. Apparently the attitude to pointe readiness in Irish is pretty much the same as that in ballet. This particular woman now has some serious problems with her feet due to going onto pointe before she was ready. She's not alone, both anecdotal evidence from colleagues as well as published research shows this is a major problem for female dancers.
The answer of course is a change in attitude in dance education, and a focus on physiological development. Dance teachers need educated in order to make decisions for their students. It's such an easy problem to fix, however as always attitudes take a long time to change, and a significant number of girls going on pointe now are still going to suffer pain in adulthood due to poor decision making on their teachers' part.