There was a Brazilian WG I used to see in Berwick Street, Soho, who over 50 when I was in my 30s. Good body on her, had lots of fun, she was a great fuck.
Also in pre-UKP days went to a Chinese place and the woman must have been well into her 50s, not very good looking to be honest, but I was there and thought what the hell. She was sitting on the bed sucking me while I was standing, then asked "You do want sex?", sounding worried that I was going to say no! I was a bit take by surprise and said of course, so she got onto the bed and I entered her from behind. Once I started pumping, she was sighing, it started feeling really good and I began to go faster. Ended up getting her to lay on the bed and I went to town on her, fucking her really hard until we both came. I didn't find her attractive at all but she was so enthusiastic I couldn't help but enjoy it.