Hi @adian. I started HRT at 63, just 5 months ago, about 10 years post menopause. I am on a low dose generic transdermal estrogen patch, .0375, twice a week, and 100mg progesterone nightly. I won't have another dexa for another 9 months so I don't have any bone feedback. I've also carefully monitored my diet and supplements and increased weightbearing and weightlifting exercise, so if I do stabilize or possibly increase density it will probably be a combination of factors.
All this being said, my starting numbers are low.
Your numbers are much more serious. Although you might benefit from HRT there seems to be more going on than estrogen loss.
It's most important to try to find the causes of your bone loss and address them. Were I you, I would have then taken an anabolic medication like Tymlos to stimulate quality bose growth and help prevent fractures.
I encourage you to search this forum on those subjects: discovering root causes of bone loss, bone marker testing, anabolic drugs, and more. There is so much information and experience here to learn from. Do a lot of reading. Try "Great Bones" by Keith McCormick to learn about bone biology and processes, medications and more.
Keep us posted! Wishing you the best in health!!