It's going to be a decision made by yourself and your doctor as to whether you should take HRT. However, my opinion is that you can't totally place ALL your faith in HRT to help with the osteopenia. It will probably go a long way towards helping your problem, but you are quite young to have started developing osteopenia, so I would be very mindful that you may also need to do other things to help prevent further bone loss.
My father had osteoporosis and broke his hip a few years before he died. My doctor has told me that when older people break hips they often don't survive much more than a couple of years. I was diagnosed with osteopenia probably in my late 40s, and I am now 55, so I am taking it very seriously because I don't want to end up like my father. His final years were miserable.
Menopause happened for me around the normal age of 50-51 and I have been on HRT now for about 3-4 years. When I had my last BMD test done about 6 months ago I was very disappointed to find that my osteopenia had gotten a little worse, despite being on HRT. I was hoping that at the very least it would be the same as it was 2 years prior. When I voiced my disappointment to my doctor she said that the HRT was helping, and that things probably would have been worse without it.
So her advice was that it was time for me to consider taking Fosamax once a week. I had been on it a couple of years ago, and it was definitely helping, but I was talked out of taking it by a naturopath I was seeing at the time. When my doctor recommended going back on to it I was reluctant, but I knew I couldn't allow the osteopenia to get any worse.
I'm a bit of a fan of Dr Elizabeth Vliet, so I checked her book to see what she said about Fosamax, and she was actually very positive about the benefits of taking it, so I decided to ignore all the interweb scaremongers and whacko naturopaths, and go back on to it. I only take it once a week and I won't know how it is working until I have my next BMD test next year, but I have hopes it will at least stop it from getting any worse, seeing as it did help when I was taking it before.
Just a tip – don't bother with the scans that a done on feet/ankles. They won't give a proper picture. Make sure your get a proper bone mineral density test done, which is a full body scan.