Some autos just don't express auto genetics. Especially if the genetics haven't been super stabilized. I've experienced this and waited for the other autos to finish flowering and then flipped to 12/12 to get it to flower. By that time the plant was a monster and I managed to get 14oz of good good and another like 6oz of larf. So if you want her to start flowering now flip to 12/12 and you'll be all set. It is unfortunate that it can happen that way, but at least it is not a total loss! Good luck with the grow!