But presumably American teens? Not teens from the UK. You have to wonder how much research was done by the Eappens before hiring LW, or a British nanny full stop. Why did they not hire an American teen if they are more experienced generally.
@Sparklingbrook
In the years before British tv became popular in America, before streaming services, before the internet, people on both sides of the Atlantic knew almost nothing about each other. People had very few points of reference and most didn't know what they didn't know. There were lots of assumptions on both sides.
They presumably made the mistake of thinking a British teen would have had the many years of babysitting under her belt that an American teen would at that age, and would have assumed from her application for the job that she had an interest in babies and young children and enjoyed looking after them. They would assume that if she didn't have an interest or found it boring or stressful, she would get work in a different area, which is what American teens would do. By 19, American teens who preferred not to work with children would have been working in offices or shops.
Also, the preference for an English speaking nanny might have played a part in their decision. Someone speaking standard English fluently may have been preferable to someone who didn't speak standard English as a first language, and it might have been hard to find someone perceived to have the youth/energy and interest plus fluency in English to provide the sort of childcare they needed for the hours they were looking at. Yes, there may have been older and more experienced nannies available, but maybe they would have families and homes of their own, maybe not willing to live in, and maybe not speaking English at the level they wished their children to be exposed to.