Polly's reply is so shameless (including promoting her own book in the reply) that it's incredible just how badly it missed the point.
> If you want to build a life with a partner, and have a more satisfying career, and maybe have children, you need to treat yourself like a treasured child starting today. If you had a daughter who was 35 years old and felt like all of her traveling and moving was a giant mistake that embodied everything BAD and shortsighted about her, what would you tell her? You’d tell her she was wrong. You’d say, “Your life is just beginning!”
This doesn't help the author and it doesn't help onlookers, either. There is a time window on opportunity. There are serious tradeoffs that need to be pondered when you reach adulthood, and almost none of them are helped with a "you deserve it!" attitude. And there are some things, like travel and careerism, that will not outlive you, like your children will.