I find this thread so interesting, but maybe not for the original opinion that Shooting Star made.

I think my lifestyle/thoughts are quite similar to Emily's, even though I have children. I feel little in common with most people my age, because we are out doing the things that younger people do. I feel guilty thinking that I hate going to the synagogue (which was a significant part of my life/social activities) because I look at the people I've known there for 20 years and they look/act old. Some appear to be handicapped by their health in some way. Even my 2 "regular" friends sometimes get on my nerves, mostly because they talk about how they "can't do this, etc" or their idea of fun is a cruise. Ugh. These 2 are both somewhat surprised of my newer friendship with someone who I met through them, but now is a rider. Yea, I brought her over to our side.
This said, most of the people I ride with are my age (58, almost 59) or older. AMC and my other riding group are full of very fit people in their 60's, 70's and beyond. These people are my role models and almost all of them have kids, so there are people who had kids and stayed active around here. Most of them do/have done a lot more than me, including some adventurous travel and many Boston Marathons. And people who are surprised that life doesn't have to end when you have kids have been a peeve of mine since, well, since I had kids. For the past 30 years, I swore that kids wouldn't change me. My kids were planned and wanted, but but I can honestly say, I am still the same person inside. Sure, it took a little planning and organizing, but most of all, it took the desire to maintain and pursue an adult life, with adult interests. My DH and I went out almost every Saturday night, with friends, or alone, and I did a ton of volunteer work, in addition to working full time. My kids turned out quite normal, despite what others might have thought at the time (like in, oh, she works all week and then gets a babysitter to go out with her DH).
What was different was the way I got my fitness. I woke up early and went to the gym at 5:30 AM, so it didn't interfere with my family. After we moved to MA from AZ, we started doing a few little outdoor things with the kids, but since we weren't that much into what we do now, it was minimal. I sincerely regret this. My kids would have loved being on the back of a bike, in a trailer or tag-along, hiking, camping. There are plenty of venues for families to do this here, but I just didn't know about this.