Germantown Friends, the Quaker school founded in 1845, has seen a glimpse of its future, and it’s not confined to Northwest Philadelphia. With millennials not only flocking to Center City but staying and having children, the school with 960 students from preschool through 12th grade, opened an early childhood and after-school program on Washington Square this fall to tap into the burgeoning market. Statistics gathered by the Center City District show that nearly 9,200 children under the age of 6 reside in greater Center City — more than children aged 6 to 17. “We studied what the need was and what our needs were and decided that we should embark on placing a pre-K in Center City,” said David J. Feldman, a member of the committee that oversees GFS and lives downtown. “You walk around any of the parks, and you practically get run over by strollers.” Germantown Friends is believed to be the first area private school to add a preschool site in Center City. “I don’t know of anyone else, ” said Barbara Kraus-Blackney, president of the Association of Delaware Valley Independent Schools, which represents private schools throughout the region. But she said she would not be surprised if other schools were considering similar programs for Center City. “We tell our schools through our programs to think about strategic ways of looking at the future, and this would certainly be one of them,” Kraus-Blackney said. “This region has so many [independent] schools; they’re not likely to be divulging their plans until they’re ready to go.” Drawing on U.S. Census data, recent reports show that millennials – young adults between the ages of 20 and 34 – make up 40 percent of the city’s downtown residents, and they tend to be educated. Fully 59 percent of the residents in greater Center City have at least an undergraduate degree. “The school committee studied in great depth to see where the children were going to be in the next five to 10 years,” said Page Fahrig-Pendse, associate head at GFS. “It is true that more younger people were moving and staying in Center City – even when they had young children. Where in the past, maybe those families moved out to the northwest. That’s