It is not so much turning years back to be something else, because, when all is said and done I have enjoyed an interesting and remunerative career in a field that really interested me and so many of the good things in life: DH, children, opportunities to follow my interests and have interesting experiences have flowed from that, but Robert Graves wrote of choosing between two paths.
Two roads diverged in a yellow wood,
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth;
Then took the other, as just as fair,
And having perhaps the better claim
............
In my case there were two other roads I would have liked to have explored more, one was becoming a child psychologist, the other a landscape archaeologist/historian. But I had no idea how you set about becoming a specialist Child Psychologist and someone, who should have known better introduced me to the other subject but never gave a hint that it could be a career, although that was the route she was going down.