Emily Kaplan is just too nice a girl to look sideways at her coach when he gives her seemingly ridiculous advice, but she came close when he told her that taking your time at the beginning of races can actually mean running faster times in the end.

But what started out as counterintuitive seemed almost natural for Kaplan on Saturday at the Independent School League championships in Derwood. Instead of using the gun-it-from-the-go style that characterized her earlier races — and caused her to burn out way too quickly — the Georgetown Visitation sophomore turned her motor down early and then burst through the 5K Agricultural History Farm Park course in 18 minutes 51 seconds.

Kaplan breezed to the league title in just her first year of participating in cross-country, and it cemented her status as the top private school girl in the Washington area.

“I was like, ‘Are you sure?’ ” Kaplan remembers thinking after Cubs Coach Kevin Hughes told her that cross-country races aren’t won during the first mile, but they sure can be lost there. “I was a little surprised.”

National Cathedral senior Polly Terzian was runner-up in 19:34, helping her school win its first ISL team title since 2008. Behind Terzian, the Eagles eked out a three-point victory over defending champion Georgetown Visitation. Georgetown Day was third.

Things weren’t nearly as close in both the Mid-Atlantic Athletic Conference and Interstate Athletic Conference championships that followed. Georgetown Day won its third straight MAC championship, easily outdistancing Sidwell Friends and St. Andrew’s. Grasshoppers Coach Anthony Belber marveled at how a school with only about 250 boys is able to overpower schools that enroll far more. “It’s thrilling. It’s such an amazing accomplishment,” he said.

Sam Dodge and Tai Dinger crossed side by side in a tie (16:26) to lead St. Albans to its fourth straight IAC title. The Bulldogs scored just 23 points, dominating Landon and Georgetown Prep.

Georgetown Day’s Griffin Colaizzi had the fastest boys’ time Saturday. He zipped through the course in 16:18, stretching his arms out to his sides as he crossed on a warm and windy day.

Kaplan ran track last year — she clocked 5:03 for 1,600 meters — but had to learn this fall how to respect cross-country as an entirely different sport. There was a pretty steep and sometimes painful learning curve.

At the Bull Run Invitational last month, Kaplan was leading the pack one mile in, but collapsed several times down the home stretch because of dehydration and staggered to a 12th-place finish. Later, she was in third place at the Octoberfest Invitational, but again ran out of gas late and finished eighth.

Kaplan was sick of finishing on fumes. On Saturday, instead of jumping out to the lead right away and wanting to see things happen too quickly, the 16-year-old took her coach’s advice and patiently allowed the race to develop before seizing her moment.

“Cross-country is even more mental than track and field,” Kaplan said. “You have to stay in it longer. I’m learning.”