The good news is that her quote appears on a US stamp.
The bad news is that it’s attributed to Maya Angelou, and Anglund isn’t getting paid for it.
Joan Walsh Anglund is an extremely famous artist of picture books, as well as an author of poetry and prose books for kids. She was probably best known in the 1970’s and 1980’s, when she also had merchandising deals with lots of card and toy companies. Her distinctive style and her old-fashioned little girls are somewhat reminiscent of the work of Kate Greenaway. The famous Holly Hobbie dolls are sometimes thought to have been styled after Anglund, although I think both were really part of a larger nostalgia trend in the 1970’s.