1) See Sally's note above.

2) It means that yikes, there are things I would do better, more wisely, more effectively if I could go back with what I know now! I have damn few regrets. But the few I have, man, I could kick them in the nuts if I could go back!

3) It means that the rather limitless energy we have as younger humans begins to fade as we age, and we have to work harder at it. (See Sally's comment above.)

Erik

Erik, I also








Erik, In thinking about it further, I too would taken more chances,not cared about " what will the neiighbors say", and in general enjoyed myself a whole lot more!!!

I think you're all right. On a personal note, I think that I got over trying to please mother. I still catch myself once in a while, asking if this action will please ME.
Now, speaking from Shaw's standpoint, with knowledge of his plays and immense biography and other writings, he spoke always and ever about himself because he was always, of necessity, the prime interest and rewardee of his life. He taught himself completely, so poor that he could not go to school, where they didn't teach him what he needed to know anyway. He taught himself to read music and to play from a score on his mother's piano. It was Richard Wagner! So after leaving Ireland, his mother and her lover amd his own job as a lowly clerk, when he was just a lad, he made his way to London where he educated himself at the British Museum and Library.
Again, knowing Shaw as I do, I believe he later in life thought of all the time he wasted in pursuing females. He considered marriage useless (his one affair, which may or not have been sexual) was with a married woman. He admired women's minds, but thought the act of sex useless too. And for them, that marriage mostly ruined their potential (read the preface to his play, Pygmalion, for instance. And by the way, Eliza marries Freddie, a completely useless man, and becomes the breadwinner. He stays home and minds the children, not that there is anything wrong with that). But reading this part of Shaw gives insight into his feelings on male-female relationship and purpose.
So my theory is, as to what Shaw meant by the questioned phrase, is that the kind of wisdom that allows us not to be deterred from purpose by our physical urges is attained only when we age. Take a look at his young people, with the exception of certain women: they are all frivolous, they are all SHAW!
But to take the phrase as we commonly do is great wisdom and comfort.

So Sally, you see it as a lament about the aging body and a comment about how young folks are naive when they think youth will last forever.

Did I get that right?

I clearly remember looking at older folks when I was in my twenties and saying, "not me." Boy, was I wrong!

Hal,

I'm with you in that I hear a component about "what I could do with the energy and vigor of youth if it were combined with my current level of wisdom/knowledge."

Speaking of cloning...if you want to transplant your brain into a "younger-you" body, you'd love my screenplay, "Blanks."

I'll dig it out for you.

Yes indeed, that is pretty much the way I see the quote. But remember, my point of view is OLD.