I was 64 when I "went unicorn". I was not large but a B cup, but people still don't notice. Even in summer clothes, people will ask me, "Do you mind telling me what kind of cancer you had?"
It's a tackless question (What if the answer was "vaginal cancer? ) but it also amuses me because they don't notice that I have one breast! I didn't want additional surgery and after radiation, my radiation oncologist told me I wasn't a candidate for reconstruction. I was delighted because that gave me a medical reason for my decision. I had no desire to hide having had cancer. It's definitely a personal decision. I found the prosthesis heavy and uncomfortable. Then during chemo I lost 58 lbs and the prothesis no longer fit. For the rare times when I wear an outfit that would look better with "two breasts" I use a knitted knocker, which is light weight and soft.
Yes, the treatment aged me considerably too. I am using a lot of moisturizer these days and as dolfina3 mentioned LaRoche-Posay has good products as well as Cere-Ve, which my dermatologist recommended. Both brands are readily available in the U.S.