"I was like, yes! Finally!" Leia told CNN affiliate KWCH. "There is no boy and girl things. There's only people things."
But not everyone is thrilled -- namely, Girl Scouts of the USA.
The competition is on
The BSA said its decision comes after years of requests from girls to join. Indeed, girls have been joining Boy Scout troops for years. It's not even the first time BSA has opened its ranks to youth who are not boys -- teen girls, for example, have been able to join its Venturing program since the late-20th century.
The announcement sparked questions about the future of the Girl Scouts and other gender-organized youth groups.
But don't expect changes from the Girl Scouts any time soon. In the interest of maintaining safe spaces for girls, boys will still not be welcome, Lopes and other GSUSA members said.
The group will keep relying on feedback from girls to shape programming, just as it has always done. Anyone gay or straight can join, Lopes said, and the group considers transgender girls on a case-by-case basis.
"It won't force us to do anything different. We are constantly looking at our programming and talking to girls. We change things if they don't work," said Sue Else, CEO of Girl Scouts of Historic Georgia, which includes Savannah, birthplace of the Girl Scouts.
One change is clear, though -- the groups will be competing against each other for members.
"We see it as more market competition," Else said, "and that's unfortunate."
What's the difference, anyway?
As the story goes, a meeting in 1912 with Sir Robert Baden-Powell, founder of Boy Scouts, inspired Juliette Gordon Low to establish Girl Scouts. The groups have been separate entities ever since, even as they pursued similar goals of building character and self-reliance through survival skills.
The GSUSA has reinvented itself over the years to keep up with the times. In 2004, it hired a management consultant to address declining membership and revitalize its volunteer system. The group unveiled a "Core Business Strategy" that led to the consolidation of councils and shuttering of camps through mergers. In addition to troop meetings and and traditional badge activities, scouts can undertake "journeys" to solve problems in their communities or learn about healthy relationships, among other projects, for badges or school credits.
The changes led to increased membership in some markets, Else said. But some parents said they came at the expense of camping and outdoor activities.
The groups share similarities, from the language in their respective pledges to merit badges. Both the Girl Scout Promise and the Boy Scout Oath vow to serve God and country and to help people at all times; both offer badges for entrepreneurship, cooking and camping.
But some badges are unique to each group. Boy Scouts have badges for rifle shooting and shotgun shooting. The Girl Scouts have badges for babysitting and hosting dinner parties; after the BSA announced the change, on GSUSA's website, the Eating for Beauty badge turned into Eating for You.
Changes in programming
By giving short shrift to outdoor activities, one troop leader says GSUSA is missing out on the chance to provide girls the one thing they can't get in school, dance or coding classes.
"We lost so many girls because of the weak programs and lack of support for outdoor activities," Erin Harvey Moody said on Facebook.
Moody's troop serves girls in California's Bay Area, Richmond and Albany -- girls who are tech savvy and yearning for outdoor activities, she told CNN. She's passionate about leading girls and wants to keep doing it in a single-gender environment. But they've only been able to retain girls by redesigning programs to resemble Boy Scout activities, she said.
"No more glitter, 'feelings jars' and 'Eating for Beauty' badges. We focused on girl-driven leadership and outdoor skills even though GSUSA doesn't have programs to support it."
BSA offered camps to Girl Scouts affected by closures. But one former camp counselor said rules and regulations hindered the experience. No nighttime campfires were allowed, and no cooking over an open flame, said Sarah Ostrowski Simmons, a former resident counselor at Camp Elliott in Volant, Pennsylvania.
"The girls got little to no actual camp experience except sleeping in a platform tent that was set up for them before they got to camp," she said. "I want my daughter to have the opportunity to camp more than once or twice a summer."
She comes from a family of scouts that includes her parents and siblings. She met her husband, a Boy Scout, through scouting. But the changes have left her disillusioned with Girl Scouts -- and delighted by the news that their daughter can now join Boy Scouts. The 4-year-old already attends meetings with her father and uncles and kind of believes she is a Boy Scout already.
"Don't get me wrong, I don't hate (the Girl Scouts). I am heartbroken and sad about how much they have changed from what I knew, loved and wanted for my daughters," she said.
She's thankful for the childhood memories she has of Girl Scouts. "But I can say without a doubt my husband and I are both very excited about this new opportunity to share a scouting world we love with our children."
Else said programming is decided among councils and troops, and that plenty of troops still offer camping and outdoors activities. The focus on science, technology, engineering and math skills is vital to ensuring that girls are prepared for the marketplace, she said.
"We have analytics that show our programming works," she said.
Eagle Scout vs. Gold Award
Perhaps the most significant change is that girls will now be eligible to earn the title of Eagle Scout, the highest rank in Boy Scouts.
The rank of Eagle Scout is a prestigious and widely recognized achievement, one that can have longterm benefits in academic, professional and even military spheres. Attorney General Jeff Sessions, Neil Armstrong and Former US Secretary of Defense Robert Gates are just a few notable men who have attained the rank of Eagle Scout.
While there is a rough equivalent in the Girl Scouts -- the Gold Award -- the honor is not nearly as well-known as the Eagle Scout distinction. But GSUSA says girls who earn the Gold Award also reap benefits, including college scholarships and the chance to skip a rank in the military.
GSUSA said 90% of female astronauts, 80% of female tech leaders, 75% of the current female senators, and all female US Secretaries of State were girl scouts. But it's not clear if any of those Girl Scouts were Gold Award recipients.
Though the Gold Award may not be as widely recognizable, it carries weight within the Girl Scouts and among employers who know about it, Else said. She acknowledged the group needs to do more to build its visibility.
"We've been striving to get those stories out," she said.
Girls Scouts girls-only?
Another touted benefit by BSA is convenience for families looking for activities sons and daughters can enjoy together -- a notion one GSUSA national board member called "a smokescreen."
Charles Garcia, a former Boy Scout, accused BSA of trying to shore up revenue following costly lawsuits stemming from abuse cases within the organization. "The Boy Scouts' house is on fire," Garcia said.
BSA rejected the allegation and said its youth protection programs are endorsed by child safety experts and psychologists.
"The Boy Scouts of America continues to be a leader on innovative youth protection policies that give our youth members the safest and most secure environment possible to enjoy our activities. The litigation referenced is related to circumstances that are decades old, and are in no way a reflection of the effectiveness of our current youth-protection policies and procedures."
GSUSA stands by the benefits of the girl-dominant environment and women as role models. It has not announced any plans to change in light of the Boy Scouts news.
"The need for female leadership has never been clearer or more urgent than it is today -- and only Girl Scouts has the expertise to give girls and young women the tools they need for success," GSUSA said after the announcement.
"We're committed to preparing the next generation of women leaders, and we're here to stay."
At least one former Girl Scout wonders if a coed scouting group -- not Boy Scouts or Girl Scouts -- would be best.
Sarah Tran, 20, of Walnut Creek, California, gave up Girl Scouts in middle school because of the focus on domestic activities, like knitting and singing Christmas carols at retirement homes. She always was jealous of the Boy Scouts' hiking and camping trips.
"I always felt like they actually learned real skills and worked on projects, went on actual hikes and camps while us girls camped on the soccer field and learned to knit. I love that girls can join Boy Scouts now, but honestly I think it would be amazing to just make one unified scouts of America group and not divide boys and girls at such a young age," she said.
"I think boys and girls can learn a lot from each other, especially at young ages. I think it's important for them to be socialized and learn together," she said. "It would be cool [for girls] to learn how to tie knots, go hiking and camp. I think it's valid for boys to learn how to knit and sing Christmas carols, too."