Beryl May was born on , at Penley Villa, Park Lane, Chippenham, Wiltshire, the eldest daughter of Agnes Dent (), , and Eustace Edward (). She was baptised at StPauls, Chippenham, on 8 June 1900. They had married at St Marys Church, Goosnargh, near Preston, Lancashire, on 27July 1898. Her mother was educated at the Harris Institute, Preston, passing examinations in science and art. She was a teacher at Attercliffe School, in northeast Sheffield, before moving to Goosnargh School, near her hometown of Preston, where her elder brother and sister, John William and Mary Ann Thornley, were the head teachers. In March 1894, she had applied for the headship at Fairfield School, Cockermouth, making the shortlist, but the board decided to appoint a local candidate.
On 18March 1889, Dents father was appointed to a teaching assistant position at Portland Road School, in Halifax, West Yorkshire, after completing a teaching apprenticeship with the school board. In the same year, Florence Emily Dent, his elder sister, was appointed head teacher at West Vale girls school, Stainland Road, Greetland, moving from the Higher Board School at Halifax. In August 1889, he obtained a first class pass in mathematics from the Halifax Mechanics Institute. He enrolled on a degree course at University College, Aberystwyth, in the Education Day Training College. In January 1894, he was awarded a first by Aberystwyth, and a first in the external University of London examinations. His first teaching post was at Coopers Company Grammar School, Bow, London, before moving to Chippenham, where he was a senior assistant teacher at the Chippenham County School.
In October 1901, Dent's father left Chippenham to become head teacher of the then recently established Warminster County School, that adjoined the Athenaeum Theatre in Warminster. The family moved to Boreham Road, Warminster, where houses were built in the early 19th century. In April 1907, they moved to 22Portway, Warminster, situated a short distance from the County School and the Athenaeum. He was elected chair of the Warminster Urban District Council from 1920 to 1922, and remained as head teacher of the County School until his retirement in August 1929.
Dents father was also a regular cast member of the Warminster Operatic Society at the Athenaeum and other venues. Dent and her younger sister, Florence Mary, would often appear with him on stage in such operettas as Snow White and the seven dwarfs and the Princess JuJu (The Golden Amulet), a Japanese operetta in three acts by Clementine Ward. In Princess JuJu, she played La La, one of the three maidens attendant on the princess, and sang the first act solo, She must be demure. In act two of the same musical, she performed in the fan dance, Spirits of the Night. She also acted in a scene from Tennysons Princess at the County School's prize giving day on 16December 1913.