Dame Jacqueline Wilson had one clear idea about her future: she was not going to write children’s books. “If I ever write, I won’t write for children,” the best-selling children’s author confided to her diary in June 1958, at the age of 12. “I can’t understand how Enid Blyton can write all day, yet leave out everything about real life.

“Her families don’t quarrel, her parents don’t nag, her teenagers aren’t interested in lipstick and boys, her children never listen to dirty stories or wet themselves, and she ignores babies and pregnancy and sex.”

This page from her journal now forms part of a new exhibition, celebrating Wilson’s life and writing career. Daydreams and Diaries: the story of Jacqueline Wilson opens tomorrow (5 April) at the Museum of Childhood in London, and traces her path from prepubescent daydreamer to author of more than 50 books, former Children’s Laureate and most-borrowed author from UK libraries of the last decade.

“She has such a huge body of work and has made such a massive impact on children’s literature,” said Gill Rennie, senior curator at the Seven Stories National Centre for Children’s Books in Newcastle, England, where the exhibition originated. “We wanted to unpick what that’s all about, and how she’s become such a huge phenomenon.”

The exhibition begins with a recreation of Wilson’s childhood bedroom, in the family’s council house in south-west London.

“I badly wanted to have a pretty pink room,” Wilson writes in the exhibition notes. “But money was tight, so I had to put up with hand-me-down brown furniture and an eiderdown to match.”

An only child, Wilson would sit in her bedroom and make up stories. The exhibition includes Meet The Maggots, written when she was nine years old, as well as an anthology of poems, each inspired by a famous painting.

And, alongside pages from her diary, there are school reports. At primary, she did well in all subjects. By secondary, however, her teachers had begun referring to her as “Jacky Daydream”. “She would rather be making up stories in her head than doing maths,” Ms Rennie said.

The exhibition tracks Wilson’s progress from teenage magazine writer to published author. Her first book, a literacy reader for schools entitled Ricky’s Birthday, appeared in 1969.

But she is best known as the author who took the elements that she believed to be lacking in children’s fiction - family quarrels, nagging parents, pregnancy and sex - and made them central themes of her books. The exhibition takes a close look at seven of her novels including her most famous, The Story of Tracy Beaker, which tells the tale of a girl growing up in a foster home.

The final section of the exhibition recreates the room in which Wilson now writes. Visitors can sit on a replica of her chaise longue and look at the decorative notebooks where she jots ideas. There is also space for fans to write and draw their reactions to the exhibits, and to leave notes for Wilson.

Patricia Wood, librarian at Ashington High School in the north-east of England, took several students to see the exhibition during its run at Seven Stories. Many of the teenagers were inspired to write their own stories after learning that Wilson had started writing while she was still at school.

“I think there was quite a lot of story-writing going on when they got back,” Ms Wood said. “They wrote about their friendship groups, what they do after school. You could see the influence there. Jacqueline Wilson writes about things that they can relate to. They’re really easy stories to read, but they’re touching on real life as well.”