Oh.....I'm soooooo sorry~
I might be alone on this but I don't agree with your doctors or the biopsy. I STILL have a hard time believing in AGA as it is, but especially when it comes to young women.
Something is OFF in your body; that is what I think. I think our "modern" western medicine just can't figure all this out...our bodies are so complicated and different.
Do you have your blood test results? Can you share them here with us?
The only thing that might help, is the Diane.....although I know it doesn't work for everyone.
What I wouldn't do is the rogaine. I myself use it, but it was after 6+ years of consistent hairloss that I threw in the towel and started rogaine.
Read through the Positive Outlook section. Take days to do it, if you need to. Do some of your own research on the internet...
I'd go with Ell Cranell, Alpecin, Folligen.....or all of them, (and Emu Oil although I feel sorry for those guys)....before the rogaine.
These are just my OPINIONS. Others might disagree with me....but 19 is so very young.
Look into your diet, gluten intolerance.....seriously. Vitamin D deficiency.
Thyroid and iodine deficiency....
Even low ferritin can mimic AGA.
Someone tell me, how do these biopsies "prove" AGA? To me, AGA only encompasses the hundreds of reasons we might be losing our hair....and to me, it's still not normal and shouldn't be something we need to live with. I think it means we need to dig deeper, but unfortunately, this is hard to do with no medical degrees and funding ourselves....
Oh, traditional chinese medicine, accupuncture.....
So many routes to look into. Is your health okay? Periods okay?
Sorry for my ramble.

I hope you find the answers you need.