Middle aged women make up a very small percentage of Couchsurfing, and when I see them they're usually hosts only. I get a ton of requests, and I think it'd be more likely for me to get a message from an astronaut than two middle aged women.
I just checked my references and my friends' references and didn't find one woman over 40. I really wonder what happened in your case!
The weirdest stay-over that I ever had was a Korean religious pilgrimage who mistook me for a monk because apparently one had lived in my apartment before I moved in.
They had loads of really interesting stories and it sounded fascinating. They'd talked about how those who had done the winter season (24 hours of pitch blackness for 4 months) were all a little bit on edge and twitchy.
My experience with CouchSurfing, on the other hand, was weird. When me and my roommates (3 guys, 2 girls) signed up our shared house (in waking distance of a touristic city center), we were expecting to see lots of backpackers and tourists our age. Instead, most of our guest requests were middle-aged women with a strong urge to point out how adventurous they were feeling. I believe we not once had a guest request from a guy.