Low Iron and B12 Causing Miniaturization?

Hi,
First I would like to thank you for providing this site, it has help me a great deal. Here is my question. I am a 31 year old female suffering from hair loss, and as of yet I do not know the definite cause. My question is concerning all that I have read about the possibility of vitamin deficiency causing hair loss in women. My doctor runs routine bloodwork every year, and for approximately the past 10 years I have had low iron, low B12, and my last set of tests, last year, did show that I also have an overactive thyroid. Throughout this time I have never taken the supplements that were advised by my doctor, I am now regretting that, and have since started. Now to the question, with being low in iron and b12 for so long cause miniaturization? I have miniaturization hairs throught my entire head, and very thin on the crown, and this is why I am questioning the effects of vitamins and hair loss. From what I have read miniaturization and thinning at the crown usually indicates AGA, however I did read once that low iron could mimic AGA with miniaturization. And I am hoping that this hair loss that I have is from low vitamins for a long period of time, and not AGA.
Thank you so much in advance.

Yes, low iron and B12 can cause hair loss. Get a good doctor to take charge of you, as that is the best approach to the problem.