She is one of hundreds of thousands of young Yemenis forced out of school since fighting escalated with a Saudi-led intervention against Shiite Huthi rebels two years ago.
The war has since killed around 7,700 people, including nearly 1,550 children, and shut down hundreds of schools.
After hers was bombed, Roua sought out classes at a mosque in her home city of Taez. But as clashes escalated, her family saw little choice but to flee.
Braving sniper fire, they walked 10 kilometres (six miles) before finding a taxi to the capital.
"I tried to register myself at a school here, but my application was rejected because the classes are overcrowded," Roua said.
"My education has stopped because of the war. I don't know what I did wrong -- I didn't do anything."
The slender 12-year-old, who loves painting and dreams of becoming a teacher, is one of 3.5 million Yemeni children out of school, according to the United Nations children's agency UNICEF.
The fighting has halted the education of nearly two million children on top of the 1.6 million already out of school before the conflict, it said.
"If Yemen's current generation misses out on school, the long-term consequences will be another generation that is likely to perpetuate the cycle of violence," it warned in a November report.
As a result, "an entire generation of children risk losing out on their future," said Shabia Mantoo, Yemen spokeswoman for the UN's refugee agency UNHCR.
Direct attacks on schools
Huthi rebels seized control of Yemen's capital in September 2014 and went on to expand their clout across the country.
As they closed in on Aden-based President Abedrabbo Mansour Hadi, forcing him into exile, the Arab coalition launched a military operation in his defence on March 26, 2015.
UNICEF has since counted 212 direct attacks on schools, including air strikes that killed pupils.
The fighting has put 1,640 Yemeni schools out of service, with 1,470 destroyed or damaged and others converted into refugee shelters or barracks for fighters, it said.
Meanwhile, in a country on the brink of famine, necessity has forced many children to beg or seek informal jobs to support their families.
Some end up joining armed groups -- the UN's High Commissioner for Human Rights says nearly 1,500 children have been recruited as fighters, mostly by the Huthis.
Ahmed Salem has lived in a camp for displaced people in Marib, east of Sanaa, since fleeing the nearby town of Sarwah. Instead of going to school, the 16-year-old spends his days trying to provide for his siblings.
"I left my education the day the fighting started in our area," he said. "Now, I go out every morning to try to get food for my family. I go to organisations again and again to try to get aid."
Although schools do operate in some areas, their work is hampered by overcrowding and frequent staff strikes over unpaid salaries. Many parents cannot afford stationery for their children.
People also fear air raids. One strike attributed to the Saudi-led coalition hit a school in northern Yemen in August, killing 10 children.
"The students are traumatised," said Abdullah al-Ezzi, a teacher at Al-Hussein school in Sanaa. "They get scared when warplanes fly over their neighbourhoods. They are scared of air strikes."
Those who drop out of school are easy prey for extremists, who have taken advantage of the conflict in Yemen to strengthen their hold on parts of the south and east.
"In the best case, (dropouts) go to unregulated, religious study centres or training courses at mosques, thinking they offer an alternative to a formal education," said Ibrahim Nagi, a teacher in Taez.
But many fear that such places are used by jihadists to radicalise and recruit young people.
Meanwhile, Roua Ahmed continues to dream of going back to school.
"Memories of my teachers and my classmates bring me to tears," she said. "I want my calm life back."
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