I found my husband's grandmother as a live-in servant, her age being given as 14 years 3 months. She was actually 13 years 10 months at the time of the census, and thus probably should have been at school, as I understand the school leaving age was raised to 14 in 1918. I wonder if her employer added a few months to her age so as not to be seen to be employing an under-age girl. Or perhaps her mother had told the employer she was a few months older than she was. Her mother was a working widow, so presumably it was convenient for her daughter to leave school early and go into service.