It's hard for children's authors to be accepted when they try to write adult books. J.K. Rowling is the exception because people are so eager to read anything by her, but it took Judy Blume three or four tries before she had a success. ↗
Mediocrity is now, as formerly, dangerous, commonly fatal, to the poet; but among even the successful writers of prose, those who rise sensibly above it are the very rarest exceptions. ↗