“I Never Wrote for Children” (New York Times, 1978) by P. L. Travers (Pamela Lyndon Travers, 1899-1996), author of “Mary Poppins” (1934)

“…I hadn't any ideas, general or specific, on literature for children and I did not set out with aims or purposes. I couldn't say that anything I had done was intended or invented. It has simply happened…

“Nothing I had written before ‘Mary Poppins’ had anything to do with children, and I have always assumed, when I thought about it at all, that she had come out of the same well of nothingness as the poetry, myth and legend that had absorbed me all my writing life…

“Moonstruck! One has to be moonstruck, which is to say, absorbed in…and in love with one's own material. Perhaps that is how it is done…

“Who, then, does write for children?…Nothing will persuade me, in spite of all his poetic protestations, that Lewis Carroll wrote his books for Alice, or, indeed, for any child. Alice was the occasion but not the cause of his long, involved, many‐leveled confabulations with the curious inner world of Charles Lutwidge Dodgson. Of course, when it was all over, when he had safely committed it to paper, he could afford a benignant smile and the assurance that it had been done for children. But do you really believe that?…

“But in the long run truth will out, as did when Beatrix Potter declared, ‘I write to please myself!’ — a statement as grand and absolute, in its own way, as Galileo's legendary ‘It moves, nevertheless.’ There is, if you notice, special flavor, a smack of inner self‐delight, about the things people write to please themselves…”

https://en.wikipedia.org/wiki/Beatrix_Potter 

https://en.wikipedia.org/wiki/And_yet_it_moves#:~:text=%22And%20yet%20it%20moves%22%20or,the%20Sun%2C%20rather%20than%20the

https://www.nytimes.com/1978/07/02/archives/i-never-wrote-for-children.html.