ESL offered by University - the first day

Today is the first class of Mont Clair University's ESL(English as a second language) class. Since the location is very near my husband's company, we decided to study there 2 hours 2 times a week in the morning. Starting the class, there were 18 students in one class, such a big class! Each student introduced themselves. Almost all of the students are Au-pair girls from 20 to 24 years old, who are from Europe and Latin America. There were only 3 Asian students, one Japanese woman who has 2 children, my husband and I. Our age is much higher than the girls. The girls can speak English fast. I didn't know about Au-pairs until I met them. Au-pair is French and describes a young person living in a host family's house in a foreign country, helping the family with childcare. I think au-pair is the way to live in a foreign country, which has an element of homestay and working holiday. They have free time to study at school when the host family's children are at school. The host family offers a car, room, insurance and feeds them 2 meals a day. It seems their work is not so hard. Otherwise one girl said that she is in a Jewish host family's house and doesn't have Internet nor a car and furthermore the host family has Shabbat(ANSOKUBI). I don't know any detailed situation about au-pairs yet. I'll interview them if I have chance.