She lived in Harrogate where she was educated at home, before attending St George's Wood Boarding School, Haslemere, Surrey.
Betty's parents were activists of the YMCA and she became heavily involved, at a very young age.
At the age of 16, she travelled with her parents to London as part of a group from the local Belgium Refugee Fund, to bring back to Harrogate refugee families who had been camping out at Alexandra Palace.
Betty worked on the project with a man named Henry Brice, who she was to stay in touch with throughout her work for the YMCA. Brice later said of her:
'If I had ever an impossible task to do, I would have put Betty to do it. And what's more, by her personality she would have got people to help her, and if she failed a hundred times, you would have found her head erect and smiling . . . her judgement was always sound, and her happy confidence in herself irresistible.'
In January 1916, one of Betty's aunts went to France to manage a YMCA Canteen in St Denis Hut, on the outskirts of Paris.
Betty was keen to join her.
At 19, she was considered too young but a month later she went anyway, paying her own expenses. She enjoyed the work, writing:
'We know how grateful the men are, and they know us now so well, I somehow feel it would be mean to leave them for a new place.'
Once her term at St Denis was completed, Betty returned to the UK but she was soon anxious to get back to France. In April 1917, she was posted to Etaples as a YMCA driver, responsible for transporting lecturers, concert parties and relatives from England visiting the wounded in hospital.
Betty described Etaples in a letter to her father:
'I'm awfully fond of the river here. There is a bridge over it from which you can get the most wonderful view of everything. On one side the river mouth and the sea and the little fishing boats; the quay and the big sailor's crucifix, where the women pray when there is a storm at sea. The boats anchor quite near; and they look like something hazy and unreal, sitting on a shiny wet river; with every sail and mast and man reflected in the water. Behind them are houses - filthy and ramshackle, but with the sun warming their pink, white and grey roofs. Behind the houses again is the camp - the tents crawling up the hill like white snails, and more hills and pines behind them. The whole thing is so illogical, boats and fisherman on the one hand, and on the other, war.'
Betty was killed by an air raid the following year, aged 21, having, despite the danger, stayed in the area to assist some French refugees.
She was given a military funeral and was posthumously awarded the Croix de Guerre avec Palme by General Petain, for courage and devotion to duty.
She was the daughter of Arthur G. and Catherine Grace Stevenson of Harrogate, Yorks.