| Any advice you get here will be purely experience only and should never be construed as actual medical advice in any way shape or form.
Now, you say she is 12 and approximately 92.4 pounds (42kg). How long ago did she get her first period? This could be just a normal adjustment time for her as it could take several years for the period to become regular.
However, I do know of a few girls who ovulate from both ovaries each month at separate times, bringing their periods approximately 12 days apart.
With that said, you really need to continue following up with her doctor as he knows her medical history. |