Hi Groundhog, sorry to hear about your surgery, I have everything crossed that it all goes smoothly for you. I was diagnosed with ovarian cancer February 2013, just before my 50th birthday so everything reproductive had to go! I can't have HRT because of the cancer but I can honestly say I haven't aged rapidly. I am still very active (horse riding, dog walking) and still feel like my old self. My main problems are night sweats (which actually start late afternoon!) and I just get on with them as best I can.
I hope this reassures you. Take care.