In less than 24 hours, more than 100 women in Elva's hometown Dublin had swiped yes to the bold idea.
"I just had this thing like, 'Hey I'm female and straight, I just want to go out dancing, does anyone want to come with me?'" Elva told news.com.au.
"I remember when going out used to be fun and I was so sick of online dating. I thought as well, if they're at home on Tinder on a Friday night too, they're probably looking for something exciting as well."
Elva also had faith that if they were swiping right to her crazy idea then "they're probably nuts too and we'd have a really good time".
The 33-year-old entrepreneur started chatting with all of the women and realised they were all struggling with similar things.
Their friends had settled down, or had kids, or were in serious relationships, "people felt like they didn't have the social life like they used to," Elva said.
Eventually Elva decided to pick two from the hundred and invited them out. She had the "best night" with one of them, clubbing until late. The other one however, didn't show.
"I completely understand that, it did sound a bit crazy," Elva said.
But the small setback didn't ruin her idea.
When she got sick of trying to message 100 separate girls on Tinder, Elva decided to create a Facebook group with all of them — not realising the idea would soon take on a life of its own.
"Everyone started to introduce themselves and they even organised a cocktail night while I was away from my computer," she said.
"I loved that they did that. A part of me was petrified like, 'What am I going to do with 100 single women who just want to go out, I had images of a Hen's Night and love going out dancing but I don't drink," she added.
Instead, Elva was pleasantly surprised.
Eventually Elva and two of her friends decided to take it nationwide, using Facebook to spread GirlCrew throughout Ireland.
"People kept telling each other about us and it kept growing by word of mouth. Obviously the plus side of Facebook is you can do so much for free and spread it internationally," Elva said.
By the end of its first year, GirlCrew had amassed tens of thousands of likes across Ireland and the team behind the fledgling network business — Elva, Aine Mulloy and Pamela Newenham — had spent $60.
"We weren't making money but it wasn't costing us anything," she said.
After two years of running GirlCrew purely through Facebook, Elva and the team eventually decided they'd delve into an app — but not before they knew it was a huge success.
"The scary thing about being an entrepreneur is if you're gonna leave your job, and as much as I love the excitement of risk, you want to know you're leaving your job for the right thing," she said.
"So we knew that this idea had already worked for 100,000 people so we launched the app when we had around 100,000-120,000 people following GirlCrew.
"We could see the pace of growth was really steady. Our second year of growth had doubled from the first and it had become really hard to manage all the Facebook groups," she added.
Since launching the app, more than 20,000 women have downloaded and are regularly using it to meet up with other like-minded women.
And GirlCrew still has more than 100,000 members in 46 cities worldwide using the Facebook groups to organise regular events including anything from hiking to swimming to bubble soccer.
The app has already launched in Melbourne and Brisbane and GirlCrew is gearing up to launch in Sydney soon, with hundreds currently on the waiting list.
There's still Facebook groups in Perth, Brisbane, Sydney and Melbourne with the GirlCrew team planning to eventually expand into Australia even more.
"It's incredibly hard sometimes but I want to make it work. I do love it and I check in with myself all the time and think 'Is this really what I want to be doing?' and every time I always tell myself, 'Yes, 100 per cent,'" Elva said.
