Only 16 students walked through the door in 1967 when three nuns from Lebanon opened a school for Armenian youth in a Southwest Philadelphia house.

But the Armenian Sisters of the Immaculate Conception held fast to their mission. They taught classes, served lunches, and drove buses as 16 grew to 225, and the rowhouse eventually was replaced by a converted Radnor estate.

Thirty-five years after the first homework assignment was given, the Armenian Sisters Academy - one of about 15 Armenian day schools in the United States and the only one in the Philadelphia-South Jersey region - is facing the same enrollment and economic challenges confronting other schools.

Student enrollment is 135, down from 225 10 years ago. The pre-K-to-8 academy is faced with the dilemma of competing against good schools in the western suburbs at a time when parents are holding their purse strings more tightly.

"I'm concerned, but I'm hopeful that the school will grow," said Sister Emma Moussayan, the school's principal.

Future plans for the independent private school include boosting recruitment efforts, expanding fund-raising sources, and finding ways to help with transportation for students who live in neighborhoods where distance is an issue, said Asadur Minasian, chairman of the school's board.

In September, the school, whose pre-K grades utilize a Montessori approach, will start a day-care program for youngsters 11/2 to 21/2.

The school's mission is to educate Armenian American youth and to pass down Armenian culture, history, and language. About 90 percent of the students are of Armenian heritage.

Among the other 10 percent are the two children of William and Kathleen Dale, who live near the school, situated on hilly, wooded Upper Gulph Road.

William Dale, an architect, is taking weekly Armenian lessons so that he can help the children with homework.

"They have really embraced us," said Kathleen Dale, who added that their children had excelled at the school. "I plan to keep [my children] there. It can only help to have Armenian on your college application."

Students explore Armenian history, poetry, and literature, and observe special events including this month's weeklong commemoration of the 1915 mass killings of Armenians by Ottoman Turks.

Many families began immigrating to the United States after the start of persecution in the 1890s, said Gerard J. Libaridian, director of the Armenian studies program at the University of Michigan.

About 25,000 Armenian Americans reside in Philadelphia and South Jersey. Other population centers include Northern and Southern California, Boston, Detroit, and New York.

The first wave of Armenian day schools were founded in the early 1960s, Libaridian said. New immigrants sent their children to the schools. But as later generations assimilate into U.S. culture, the schools can continue to thrive in Armenian communities that are large and close-knit, Libaridian said.

In the last 10 years at least two Armenian day schools - in the Detroit and Boston areas - have closed, Libaridian said.

In Philadelphia, the population is stable as new immigrants continue to arrive, but residents are increasingly dispersed throughout the region, said Ara Chalian, chairman of the Armenian National Committee of Pennsylvania.

There are increasing rates of intermarriage, and some families are opting to send youngsters to Saturday and Sunday Armenian classes at schools affiliated with churches and youth organizations, said the Rev. Hakob Gevorgyan, pastor of Holy Trinity Armenian Apostolic Church in Cheltenham.

"It depends on the family," Gevorgyan said, "Some care. Some don't."

The parents, alumni, and teachers at the Armenian Sisters Academy care a lot.

Silva Santerian, a 1977 graduate, is the mother of three children who also graduated from the academy. When Santerian lived in Bucks County, she drove her children to the school, an hour each way.

"The academics are stellar, and the school instills a love of faith and culture," Santerian said.

Former teachers include Vartan Gregorian, former president of Brown University and current president of the Carnegie Corp. of New York.

As a student, Santerian learned French and religion from Sister Hripsime Tcheftelian, one of the school's founders.

"We sent out 2,000 letters to Armenian families," said Sister Hripsime, 85, as she recounted the school's start. "Five parents responded."

Over the years, enrollment grew and benefactors signed on. The board expanded to include members of five local Armenian churches, representing three different denominations. The school moved to Newtown Square and finally to the Radnor estate. An addition to the facility was built in 2004.

As the community considers the school's future, Chalian believes the academy is more important than ever.

"The school gives you a cultural identity that complements what you get in your American world," Chalian said. "Some people have to travel to get it. Here you can just go to the Armenian Sisters Academy."

Contact Kristin E. Holmes at 610-313-8211 or kholmes@phillynews.com.