Rosie, I think that a local group ride is more of a hammer thing and lots of us "older women" do not want to always compete with the older guys. My DH is ALWAYS ahead of me on rides. He is a stronger, better rider but it would be nice to ride with him sometimes. The guys like to show off their abilities and they just press on much faster! Now, with that said...
On Bike Virginia last month, there were tons of over-50 women. The pace is much slower, the women tend to come together to the ride or with significant others and they ride together. I was amazed that they said the men/women ratio was 60/40 this year. Three years ago on my first Cycle North Carolina it was 80/20.