When Kathleen Stewart left her high-pressure job five years ago to open a day-care center in her Leesburg home, she had a skeptical boyfriend, a tiny apartment with barely enough room for toys and two children of her own who, despite being in their early twenties, lived at home and quickly became resentful of Stewart's new charges.

Today, Stewart, 45, is Loudoun County's emblem of successful child-care service and often is called upon to share her story with the increasing number of people hoping to make a living by caring for the county's rapidly growing population of children.

Recently, Stewart, whose name was Kathleen Robinson when she started her business, was a guest speaker at a seminar on starting a child-care business, a bimonthly event held by the Loudoun County Agricultural Extension Office, which runs such programs as the 4-H Club. Stewart spoke to about 15 women--and one boyfriend--about how to set up activities for children, how to deal with harried parents, how to set fees--and how busy she is keeping up with demand for one of the most sought-after services in Loudoun.

The market has become attractive to some national players in the child-care industry, including Mulberry Child Care Centers, which recently acquired Unicity Schools, of Ashburn. Unicity operates three centers in Loudoun, and Mulberry hopes to add more.

"We're looking to expand in [Loudoun]," said Rebecca Sandy, director of marketing for Mulberry. "The demographics are very good."

Four years ago, there were 22 regulated child-care providers in Loudoun, according to the extension office. Today, there are 151 and counting, with plenty of room for more as the county adds 12,000 new residents a year, said Beverly Samuel, an extension agent who runs the day-care workshop.

Many of the newcomers are scrambling to find child-care arrangements.

The need is so great that last month, executives of America Online Inc., of Dulles, developed an outreach program to learn more about the child-care issues facing employees and to get feedback on how the company might help.

The company has held several employee focus groups and has found that workers are eager to talk about the situation.

"In Loudoun County in particular, with 3,000 employees, there is a need and a demand for child care," said Jim Whitney, a spokesman for AOL, who said the pressure on the company to offer solutions is increasing steadily.

By the beginning of 2000, Whitney said, the company will have completed a "comprehensive assessment" of employees' child-care needs and developed a range of solutions, possibly including opening an on-site day-care center. The company now uses a service called Dependent Care Connection, an online service that helps locate child-care providers for employees. The service provides a list of options in the area, including home-based providers.

The women at the extension seminar, many of whom are mothers themselves, are aware that they're entering a hot industry--and they see Stewart as an example of the success they could have.

They took notes as Stewart described how she holds monthly meetings with parents to make sure they feel included in the care of their children and how she determines her fees. Stewart said she charges about $70 a week for before- and after-school care, a shock to some members of the audience, one of whom said she is paying a provider $350 a week to care for her two children when they aren't in school. Stewart said she sets her fees according to what others in her area are charging--she does not like to undercut her six neighbors who also run day-care businesses.

Despite her rough start, Stewart was able to make enough money to buy a house big enough to dedicate an entire floor to her company, Quality Steps.

But in her remarks to the eager group, Stewart warned them to resist the temptation to grow too quickly.

Samuel agreed, saying many people rush to make a profit and sacrifice sanity.

During one part of the evening, Samuel had the attendees take a quiz to find out how well suited they are to child care--she forbids the use of the term baby-sitting in her seminars.

The quiz asks participants to indicate yes, no or sometimes to such statements as, "I can handle a child's tantrums and spilled milk diplomatically" and "I can handle the stress of children tugging at me ceaselessly all day."

Stewart, who began her business with five children to watch, said even starting with a few children can be mentally exhausting. "It was crazy," she said of her first several months.

Stewart's husband, Warren--her fiance at the time--was worried that Stewart wouldn't make any money, and he wasn't enthusiastic about her decision to leave her job as a private investigator for Shoppers Food Warehouse. He has since become a convert: He helps her grind fruit for baby food and does all the cooking for the business.

But money was tight the first several months. Stewart spent many Saturdays driving from yard sale to yard sale to buy equipment and made regular trips to the Salvation Army. Now that she cares for 33 children (state licensing allows home-based providers to care for only 12 at a time, and therefore Stewart never has all 33 children at once), she still tries to save money wherever she can.

"Dollar Stores are the best place to go," she said.

Neighbors are also a great resource, she said, and will often drop off old toys or donate extra crayons.

In some ways, Stewart said she thinks the lean times might have been better for the children.

"Because I was limited in supplies, the children learned how to share," she joked.

CAPTION: Kathleen Stewart holds 1-year-old Taylor Green, one of her charges. She started her successful day-care business, Quality Steps, in her Leesburg home five years ago.

CAPTION: Kathleen Stewart checks in on a sleeping Deborah Allnutt as she heads upstairs.

CAPTION: Employee Melissa Smith, center, helps string beads with Margaret Allnutt, left, Ajah Fredzees and Caleb James Saunders.