I just checked that "how old" web site and got 35, 37, 43, and 52, depending on the photo. I'm 57. I'm frequently told by others that I look to be between 35-45. I don't know if I believe that but I've heard it enough. Before that, I was a "dignified older man" according to some.
I think there are a lot of factors, not just HRT, that color perceptions.