Kathy Golden was a picture of promise that night of her freshman year in college, as she sat down in the kitchen of her family's comfortable home in suburban Philadelphia and told her mother she wanted to become a nun.

"She was sitting in the kitchen, all in pink, dressed in those, you know, those overalls like toddlers wear," said her mother, Jeannette Golden, as she looked over at her husband and sighed. "And she had lots of blonde curls."

Yesterday, a white sari draped from head to sandaled foot, Kathy Golden, 26, fulfilled that promise in a way her family cannot completely understand, becoming Sister Gabriel of the Missionaries of Charity, the order of Roman Catholic nuns founded by Mother Teresa of India.

Under the eyes of her parents, who run a restaurant, and her five siblings, several of whom are in business, Golden vowed yesterday to give up almost all material goods in order to work among "the poorest of the poor," a phrase coined by Mother Teresa to include the terminally ill, the elderly poor and others who cannot find care anywhere else.

Golden and 13 other women took their vows at the Church of the Nativity in Northwest Washington, choosing to join a community of nuns that has grown 33 percent in the past five years, to about 3,000, according to Catholic officials. The order operates three missions in Washington, including a home for patients with AIDS and other terminal illnesses.

Promising to live in poverty, be obedient, chaste and serve the poor, the women agreed to do what dwindling numbers of Catholic women are willing to do in an age of unprecedented career choices. The number of women in Catholic orders and communities is steadily declining, official records show, to about 121,000 today, a drop of nearly 10 percent in five years.

The Missionaries of Charity, many Catholics would agree, is among the most demanding of religious communities. Its missions, which number more than 350 around the world, run entirely on charity and require the sisters to give up such everyday pleasures as television and chocolate, as well as regular family visits, in order to devote their time to working among society's rejects.

"Vacation for these women means spiritual retreat in prayer," said Msgr. William Curlin, who invited Mother Teresa to bring her novices to Nativity from their training stations in San Francisco and the Bronx.

Yet it is the very toughness of the demands that draws them in, the new converts say.

"If you're going to give up anything, why not everything?" said one of Golden's new colleagues, Sister Alison Whelton, a French major at a Canadian college who said she came to her decision to join the Missionaries of Charity "gradually, very gradually."

How does she explain her decision? Whelton was asked. "For the most part, I do not try," she said with a smile and a shrug.

Her family, it seems, had its share of discussions about the question. "Alison has a sister who's a lawyer, a brother who's a doctor. What we feel is she could have had professions like that and enjoyed life more," said Nora Nickel, Whelton's aunt.

But Nickel, a resident of Schenectedy, N.Y., was not about to miss the ceremony. Nor were the more than 1,000 others who crammed into the cavernous church.

Some arrived as early as 7 a.m. to take front-row seats in order to see the young faithful and their mentor, Mother Teresa, who won the Nobel Peace Prize in 1979 and has drawn local attention because of her home for AIDS patients on Otis Street NE.

In a short homily yesterday, Mother Teresa urged the audience, particularly the parents, to rejoice knowing that the love these women received in their families played a part in their desire to do good.

"We are proud," Jeannette Golden had said earlier, "but it's also sad . . . . I ask people, 'Do you remember what it was like when you took your child to kindergarten the first day?' It's like that, but you can't go back at 3 o'clock and pick them up."

Golden uses her experience as a parent to try to understand her daughter. "I would do anything for my child," Golden said. "She says she would do anything for Jesus."

Do any of her other children have similar ambitions? "I think it's fair to say, no way," Golden said.

Kathy Golden's sister Jane, 24, remembered fighting with her as a teen-ager: "We shared a bedroom; she was neat and I was messy." A younger brother, Mike, said his older sister was "bossy, sometimes." But both said that Kathy, more than the other children, was the first in their family to help someone out, and spent much of her youth doing volunteer work for the disabled and for Philadelphia's street people.

Whelton, too, showed a willingness to serve others as a child, her older sister Carmel Whelton said, even as she strove to be first in everything she did. "She was always the first in our family to go on wild rides {at an amusement park}," Carmel Whelton said. "She'd go off the high board in swimming and I wouldn't."

The new sisters must renew yesterday's pledges once each year for five years, at which point they take a vow for life. Occasionally, sisters leave the order, a point of some discussion in the Whelton household.

"My younger sister says their initials -- MC -- stands for might change," Carmel Whelton said.