Navy (16-3) will play Johns Hopkins in the opening round of the NCAA tournament. (Jonathan Newton/The Washington Post)

Donna Collins was apprehensive when her identical twin daughters, Jenna and Julia, decided to play lacrosse together at the Naval Academy. A fierce sibling rivalry colored nearly everything they did growing up in Clarksville, Md., from intense basketball games in the driveway to races around the house. Donna wasn’t quite sure how carrying the competition into college would work out.

“I couldn’t stand it when they were young. The competitiveness was so bad!” Donna said. “When they were 3 years old, they would fight about who got to get carried up the stairs first. One was a little more aggressive, a bit more of a bull. I thought they could use that separation in college. But it turned out they just wanted to stay together.”

That competitiveness continued right up until the Collins twins committed to Navy in the fall of their senior year in high school, when Jenna — the bull — announced her decision five minutes before her sister while the two were playing in a club tournament hosted by Navy.

“We were dead set,” Jenna said one recent afternoon, glancing at her sister before both broke into giggles. “I couldn’t wait.”

It was to Navy’s benefit that the pair decided to stick together.

The Collins twins have redirected their competitiveness toward opposing defenses for the past four years in Annapolis, where the seniors have developed into elite scorers who have helped bump Navy to the foreground in women’s lacrosse. This year, Jenna leads the Midshipmen in goals with 75, fifth most in the nation, and Julia sits second on the team with 59. They will lead an experienced offense Friday as Navy (16-3) faces Johns Hopkins (10-8) in the opening round of the NCAA tournament at Loyola University in Baltimore.

Jenna Collins leads Navy and ranks fifth in the nation with 75 goals this season. (Jonathan Newton/The Washington Post)

Last year, they were a big part of the Midshipmen’s historic run to the Final Four. Navy upset defending champion North Carolina in the quarterfinals to become the first service academy team to compete in the national semifinals.

“That North Carolina win last year put Navy lacrosse on the map,” said Halley Quillinan Griggs, the women’s editor for Inside Lacrosse magazine. “The key players that are back this year, the Collins twins and Kelly Larkin, had a big role in that. Jenna Collins is probably one of the top three midfielders in the country this year.”

Jenna has received more national attention than her sister, who plays attack. At Navy, she’s one of the best scorers Hall of Fame Coach Cindy Timchal has had, and she’s poised to break school records this weekend. Jenna needs three goals to break Navy’s single-season record and two to break the career mark (she has 216).

The on-field success isn’t new to the Collins girls — Jenna and Julia were high school stars in lacrosse and basketball and competed in back-to-back state basketball championship games for River Hill. They lost both to a team with another pair of powerhouse sisters: Brionna and Stephanie Jones, who went on to play basketball at Maryland.

But the recognition at Navy is different. Classmates curious about how the lacrosse team is doing stop the Collins twins on the Yard, as the campus is called, to give well wishes.

Julia Collins has 59 goals this season, ranking second for Navy. (Jonathan Newton/The Washington Post)

“It means a lot, especially to be a women’s sport at the Naval Academy,” Jenna said. “To make it that far means a lot because we’re a minority there. At any academy, women are in the minority. We’re only 25 percent! So it’s just awesome to be a women’s team making a difference.”

Timchal knows the local recruiting scene as well as anyone in the sport, and since arriving at Navy in 2006, she has been smart about going after talented but lightly recruited players. The Collins sisters had good options out of high school in James Madison, Louisville and Towson, but they weren’t at the top of recruiting lists.

Larkin, the team’s standout sophomore and points leader, went under the radar as a recruit out of Bishop Ireton in Northern Virginia because of an injury. Navy gladly snatched her up.

Now their success is great advertising for Navy in a region in which top recruits have perennial NCAA title contenders to choose from — schools that don’t have the added consideration of a service requirement.

“It’s not for everybody, but for those who kind of just want to stand out, like the Collins twins, I think that’s where young women look at this as an opportunity to have a great college experience,” Timchal said. “Now we’ve proved we can compete truly at the highest level. It does help with getting great players, in addition to everything else the Naval Academy has to offer.”

The Collins twins are hoping still to be playing during graduation this year; the Final Four falls on the same day as Navy’s ceremony. After that, both will head to flight school in Pensacola, Fla.

“This program’s just going to grow and grow. I can’t wait to come back and see what it’s like,” Julia said. “Flight school’s going to be good, too. A few of our teammates will be there with us — of course, we’re going to live together.”