Is it possible/not improbable) for a woman to fail to meet the right one in her 20s, yet she manages to find the right one in her 30s, 40s and even 50s?
Oh. Then yeah, it's possible. In your teens and 20s, most of the people you meet are the result of choices you didn't make--where your parents decided to live, where you were able to go to college, who hired your for your first job, etc.
Once you get a bit older and have your own career, interests, hobbies, etc. you have a lot more self-determination, so you're going to meet more people who are like you (vs. people who randomly happened to cross your path). That's gotta up your chances of meeting someone you're more compatible with.
There's a reason why so many couples who marry young end up getting divorced.
Yeah, I know many women who have active dating lives in their 50s-60s. My mom's friend last year started seeing a guy she knew in high school who used to be married to her best friend, but was widowed. He's a great guy, doctor, and they get along great. That's one of many examples in my life. People are getting divorced at all ages and looking for someone new. I don't believe in "the one" but you can find very compatible people, as someone here said.