which was her first work as a writer?
"Mrs Beeton's Book of Household Management".
Isabella Beeton
Her name is particularly associated with her first book, the 1861 work "Mrs Beeton's Book of Household Management". 
who is isabella beeton? An English journalist, editor and writer. where was she born? London.
wiki:13551994
Isabella Beeton [SEP] Introduction
Isabella Mary Beeton (' Mayson; 14 March 1836 – 6 February 1865), known as Mrs Beeton"', was an English journalist, editor and writer. Her name is particularly associated with her first book, the 1861 work "Mrs Beeton's Book of Household Management". She was born in London. After schooling in Islington, north London, and Heidelberg, Germany, she married Samuel Orchart Beeton, an ambitious publisher and magazine editor. In 1857, less than a year after the wedding, Beeton began writing for one of her husband's publications, "The Englishwoman's Domestic Magazine". She translated French fiction and wrote the cookery column, though all the recipes were plagiarised from other works or sent in by the magazine's readers.