But when Diaz, still a few weeks shy of her 18th birthday, finally asked her mom to sign the papers permitting her enlistment in the U.S. Marine Corps, Ofelia Guerra was hesitant.
"I was hoping that she would change her mind," said Guerra, whose home in West Valley City is adorned with photographs of all of her children, including a large portrait of her stern-faced daughter in her Marine dress blues. "I wanted her to be an attorney."
Women make up about 14 percent of the U.S. military - and just 6 percent of the Marine Corps. Military officials say female service members are expected to perform and be treated the same as their male counterparts once they've enlisted - but recruiters and academics who study the issue say the process for recruiting women, and their parents, is subtly different.
In its recruiting efforts, the military "may try to reassure potential recruits and their families that women in the military don't lose their femininity, even though they are joining an institution known for conferring masculinity and making men out of boys," writes Melissa Brown in her paper, "A Woman in the Army is Still a Woman," which evaluates the gender messages of decades of recruiting materials. Brown, a professor at City University of New York, took the title of her paper from an Army advertisement directed at potential female soldiers.
Brown found that females in military advertisements are often not pictured in uniform. Indeed, that's the case in a video ad currently posted on GoArmy.com - the Website for the U.S. Army Recruiting Command. The video pictures dozens of soldiers - only three of whom were identifiably female. Two of the women pictured were in non-combat uniforms - one in a white lab coat and another in a firefighter's uniform - and none were shown carrying weapons, as many of the men were.
The ad reflects realities Sgt. Marietta Sparacino sees every day in her job as an Army recruiter in Salt Lake and Davis counties.
"The males are much more into the range - shooting weapons and everything. The females, not so much," Sparacino said.
Sparacino, an Army truck driver by training, said some women do express interest in army weapons, vehicles "and jumping out of planes," but she said she doesn't make that assumption from the onset as frequently as she would with a male recruit. "We have to get to know them to find out what their passions are."
The military as a whole may need to hone its wartime message, however. The number of females serving in the Armed Forces has fallen every year since 2003, the year of the U.S.-led invasion of Iraq, according to figures from the Pentagon's Statistical Information Analysis Division.
Recruiting can be a tough business during war. U.S. Army Recruiting Command spokesman Douglas Smith said recruiters are spending more time, these days, talking to would-be recruits and "influencers" - the military's word for parents, spouses and friends - about the subject of war. And, Smith said, "the parents of a young lady might be more concerned than the parents of a young man that we are an Army at war."
That was the case for Guerra. It took several days of cajoling on the part of her daughter and her daughter's recruiter to convince her to sign the papers permitting the girl's enlistment.
"My mother said that she did not want me to join because she didn't want them to send me to Iraq," said Diaz-Guerra, who is currently stationed at Camp Taqaddum, a supply point serving larger bases in Ramadi and Fallujah, in Iraq's western Anbar Province. "I told her that if that was the case, that was something I knew and I was OK with it - that I wanted to do something useful with my life, something that I could tell my children and their children and be proud."
Guerra said she still feels sad about her daughter's decision - particularly now that she's away at war. But leafing through a photo album of her daughter's quinceañera - Diaz-Guerra wore an extravagant blue dress for her 15th birthday celebration - Guerra said many of the things she once worried about have gone away.
"Even in uniform, she's such a beautiful girl," Guerra said.
And for the moment, Guerra said, she has bigger things to worry about.