"It all seems a bit surreal," said the 38-year-old, who has worked at Maids Moreton Church of England infants in Buckingham for the past seven years.
"I started writing stories when I had children and I have about 30 stories in a drawer somewhere, but I never expected anything to come of it."
Her story of a boy called Milo who learns to have the confidence to be himself won a picture book competition, organised by Little Tiger Press publishers. The prize is pound;2,000 and a contract to publish the book, entitled I am special, I'm me!, which should hit the shelves next autumn.
Mrs Meek would not have entered the competition but for some good-natured nagging from her husband Neil and daughters, Holly, 12, Gemma, 14, and Kayleigh, 16. "They were just over the moon when we found out I had won. We were all jumping around, screaming," she said.
Her story was the unanimous choice from a shortlist of 12 finalists.
Children's author Vivian French, one of the judges, said: "Ann's story has a warmth and lightness of touch. What's great is that it is the child who makes the final step - the mother doesn't solve his problems, but just gives him the lead."
Mrs Meek, a former accounts supervisor, draws her inspiration from pupils at Maids Moreton infants.
"Milo is a combination of lots of different children," she said. "I sometimes see children with low self-confidence - I wanted to help boost their self-confidence with a story."
She has written three more stories featuring Milo, including one in which he loses his imagination.
Mrs Meek put her win down to her approach to life. "I am 38 going on three.
My family bought me fairy wings and a wand for Christmas last year - I am just a big child at heart.
"My husband says I have been working with children for too long. But when you are writing, it's important to see things from a child's perspective."
Mrs Meek is starting a teacher-training course next year, but the extra workload will not stop her writing. "I will still do it as a hobby because it is something I enjoy, but it's nice to know you have got a foot in the door. The trouble is that everybody compares you to JK Rowling."