We first went to CSA when we were your age and we were some of the younger people there but there were others. When we were there this past April there were many younger than us but also many older. The oldest person I met was well into her 80's. She was there for her great granddaughter's wedding. I sort of prefer the older crowd. They are polite, respectful, fun to talk to and not loud an obnoxious like many of the younger couples that were there at the time. Most of the people there are nice, no matter how old they are.
We just came back from CTI and I would say the age was tilted in favor of younger, but after the weekend and a large wedding and their guests left, it went back to being spread out evenly. We met and made friends with people 20 years older and 20 years younger than us (yes we are about 40. I will say that if you're looking for a spring break type of crowd, Couples won't be the place for you.