Margaret Domka was 4 years old when she learned to play soccer and started refereeing at 13 to earn money in high school.

Starting this weekend, she will be on the field as the best women soccer players on the planet meet for the World Cup in Canada.

The Wisconsin native will be the one with the whistle.

"When I started as a referee it was just a summer job in high school, and I never imagined any of this could happen. But over the last five years it's been a goal and a dream to go to the World Cup," Domka said in a recent phone interview before leaving for Canada.

She's one of 29 referees, and the only representative from the United States, selected for the Women's World Cup. Under FIFA rules, only female referees are assigned to women's tournaments and only male referees handle men's tournaments.

This year's tournament features 52 matches in six Canadian cities with the championship game on July 5 in Vancouver.

Domka, 35, grew up in Stevens Point and was a defender on the Wisconsin-Stevens Point women's soccer team, which in her senior year advanced into the women's NCAA Division III Final Four in 2000. That year she was a D-III first-team All-America.

Four years later, Domka became the first female to officiate a Milwaukee Wave game.

She steadily rose through the officiating ranks until becoming a FIFA international assistant referee — the officials with flags on the sidelines — in 2007 and '08. She has been a FIFA referee on the field since 2009, becoming the 10th FIFA-certified international referee and third female in the U.S. She has worked as a referee in the National Women's Soccer League and in Portugal at the Algarve Cup in 2012 and '13.

Before the World Cup, she officiated at the past two FIFA U-20 Women's World Cups, in Japan in 2012 and Canada last year.

The competition in Japan "was the first time I had done a World Cup tournament. That was the first time I thought the full Women's World Cup would be a possibility," she said.

Though she's making quite a name for herself as a referee, Domka has been a longtime Spanish teacher at Union Grove High School, south of Milwaukee. Her students organized a small party shortly before she left for Canada.

At the Women's World Cup, she won't know her assignments until 48 hours before game time and like all referees, she will not officiate a match involving her home country. Her parents in Stevens Point, whom she calls her biggest fans, will have to watch her games on TV because they can't travel on short notice to wherever she is sent.

Playing soccer for so many years helped her become a better referee, Domka said, making it easier to understand aspects of the game from a player's viewpoint. And there isn't much difference when officiating a men's or women's game.

"I think players will always try to see what they can gain from the referee," she said. "I'm not sure I'm any different in that respect. Certainly players will try to adjust my viewpoint at times, but I don't think that's because I'm a woman."