"We were kind of on the edge," says Henry. "There was some trepidation. We knew we weren't pulling in enough revenue to support ourselves. But we knew we could move a lot faster if we worked on [Given.to] full time."
So what accounts for millennials' adventures into passion-fueled self-employment?
Being young and unencumbered certainly helps, as both Messinger and Millman will attest.
Messinger and his cofounder are both single and have low living expenses, in part because of "the really low cost of living" in Baltimore, he says.
While Millman now shares space with her fiance, their two incomes go mainly toward paying a mortgage, other bills and groceries.
"I think it's definitely a bonus that we're both 25 years old; we don't have children; we're not planning to have children anytime soon," she says. "We don't have crazy financial obligations. What better time than now when I am young and I have minimal obligations, so by the time the business is successful, it will pay for things that come?"
And for young people getting into entrepreneurship, especially those wanting to found a tech startup, timing has never been more opportune, according to Tom Kuegler, co-founder and managing partner of venture capital firm Wasabi Ventures.
The firm's main operations are in Silicon Valley, but Kuegler is a native of Essex, and he spends a good chunk of his time every month visiting with or talking to Baltimore-based startups into which Wasabi has invested money.
"There is more access to early capital than there ever has been in the existence of the U.S.," he says. "You can feel it when you have conversations with people: 'I can raise $250,000 to $750,000.' Twenty years ago that wasn't even remotely possible." For example, a U.S. Securities and Exchange Commission filing shows that Messinger's startup raised $160,000 for its first round of funding in 2012.
To date, Common Curriculum has raised $420,000, $100,000 of which came from the Maryland Technology Development Corp. TEDCO, as it's commonly known, was created by the Maryland General Assembly in 1998 and uses taxpayer dollars to invest in early-stage startups.
Even in a down economy, venture capital groups in the area, Kuegler's Wasabi Ventures among them, have money to dole out to start-ups they deem deserving.
The Baltimore Angels, whose members include entrepreneurs like Greg Cangialosi who have pocketed serious cash for selling their startups to bigger companies, made investments totaling $850,000 in eight Baltimore-area startups in 2012.
Lest millennials believe the grass is invariably greener in the moneyed pastures of self-employment, not every entrepreneur will become a 21st-century Rockefeller.
Kuegler notes that many startup ventures _ especially those in the tech industry, can and will fail. Henry says that since returning to Baltimore in late 2012, he and his Given.to cofounders have gone back to working full-time jobs.
"It's not a sure thing if you're going to be successful or not," he says.
Not to mention that going out on one's own will inevitably lead to times when one, to appropriate language millennials sometimes invoke, literally can't even.
"I've had days where if one person says no to me, I feel really down," Millman says. "Some days I wake up and think: Why did I do this?"
Messinger compares the arduousness of raising money for Common Curriculum to the laboriousness of first-year teaching.
"You don't realize how hard it is [and] how risky it is. You haven't seen the stories of other people trying and failing," he says. The struggle is indeed real.
But Henry also points out that one failure "doesn't mean you're done as an entrepreneur." He freelances at Jinici, a Baltimore-based Web design and development company. He now works full time as a web developer at an advertising agency.
And if trends continue and patterns converge, it seems likely that millennials will make up a greater percentage of the roughly 16 million Americans who are self-employed.
Those like Millman are at least getting an early start.