As she wraps up her freshman year at Lincoln High School, the teen with a passion for nonprofit work and a knack for raising money is preparing for her next project: a family Habitat for Humanity trip to Guatemala.

PORTLAND — On a tidy shelf in a bright turquoise bedroom in Southwest Portland sits a framed certificate from the Cambodian Ministry of Education. It is written in Khmer, the official language of the Southeast Asian nation, except for a name: Christina Schmidt.

The document, essentially a fancy thank-you note, was presented to the 15-year-old last winter in a tiny village about a day's drive northwest of Phnom Penh after she helped raise more than $16,000 to build a secondary school in the impoverished country. "I feel like it's part of my duty to give back and to help others who aren't as lucky as I've been," Schmidt said.

Now, as she wraps up her freshman year at Lincoln High School, the teen with a passion for nonprofit work and a knack for raising money is preparing for her next project: a family Habitat for Humanity trip to Guatemala. She and her 13-year-old brother, Andrew, have raised $2,000 to put toward construction supplies. They will donate their time to build a house with the family that will live in it.

Schmidt, sitting at her dining room table, traces her interest in humanitarian work to a 2007 family vacation to Vietnam and Laos that introduced her to life in developing countries.

She got involved with Cambodia a few months later while considering what do the next year for her eighth-grade project, required of students at Arbor School of Arts & Sciences, the private school she attended in Tualatin. An e-mail from her dad held the answer. It contained a news article about a girl who raised thousands of dollars for American Assistance for Cambodia, a nonprofit that builds schools. As soon as she read it, she rushed downstairs to her dad's home office.

"This is what I want to do," she told him. "I want to do this." Her excitement surprised her father, David Schmidt, a pulmonary specialist at Kaiser Sunnyside Medical Center.

"I didn't intend for her to do that exact project," he said. "But she grabbed onto it kind of like grabbing a bull by the horns."

Before jumping in, Christina Schmidt tracked down and pored over American Assistance for Cambodia's tax records. "They use every single cent that they get so well," she said.

She also learned that if she could raise $13,000, it would be matched with $20,000 from the World Bank and Asian Development Bank — enough to build a school.

Next, Schmidt had to track down a professional to work with, a requirement of her school. She found a mentor in Kim Freed, former managing director of the Oregon Zoo Foundation, who had years of fundraising experience.

Freed said she was nervous when she heard that Schmidt planned to raise $13,000 in nine months.

"But I could tell by her determination and her energy that she was going to see it happen," Freed said. "I was very much inspired by her."

Bernie Krisher, former Newsweek Tokyo bureau chief and founder of American Assistance for Cambodia, said schoolchildren often work together to raise money to build schools, but only a very few can accomplish the goal on their own.

"They are very compassionate," Krisher, who has corresponded with Schmidt by e-mail, said of children who devote time and money to advancing education around the world. "They're going to contribute a great deal and learn a lot and probably succeed in life."

Schmidt kicked of a 300-letter fundraising campaing and secured small grants from two foundations. Then during her 2008 winter break, her family traveled to Cambodia on vacation, and Schmidt got the chance to visit an American Assistance school.

Interacting with the students brought her project to a "whole other level," she said. She keeps a gift from them, a frosted blue binder filled with colorful drawings, next to the certificate on her bedroom shelf.

Her favorite drawing, of a yellow and red sun overlooking a field of purple flowers, came with a message: "Hello! My name is Kunthea." She was touched that he made an effort to write in English. "I just thought that was so sweet."

Schmidt and her father returned to Cambodia a year later to attend a dedication ceremony for the school she helped pay for: The Arbor School of Hope. The 80 students lined up in their crisp white shirts and navy slacks and skirts to greet her. They giggled when she said hello in their language: "Johm ree-uhp soo-uh!"

In the end, she raised $16,235.14. Now she's working to use the extra money to secure a water filter and textbooks for the three-room, shingle-roofed school. She has also become interested in water scarcity issues, recently participating in Portland's Walk for Water and helping with awareness days through her high school's Mercy Corps club.

"Christina's always been pretty confident," said her mother, Jennifer Schmidt, who's taking the year off from teaching. "But ever since the project, she seems much older and more mature."

Christina Schmidt is grateful for the outpouring of support she received. She keeps a zip-close bag filled with letters from donors in a cabinet below the certificate of thanks.

"They're just really important to me," she said of the letters. "Because the school wasn't really built by me. It was all the people who gave the money who really deserve the recognition, because without them, it wouldn't have happened."