There, in black and white, her grandfather and other relatives, all bearing distinctly Muslim Albanian names, were listed as born in Greece.
"It's surefire proof we are Greeks," Mustafaj, 65, told Reuters in the village of Shengjergj in Albania's eastern Korce region.
"My father's name was Dionysus, but they renamed him Dervish," she said.
"I knew where my roots were but the (communist) system tried to change it. We're not trying to sell out our country or buy into another, we're just exercising our right to say who we are."
Statements like Mustafaj's are causing waves in Albania, where for the first time since communism was toppled in 1990 residents are being asked to specify their ethnicity in a national census.
In Shengjergj, a village of shiny new villas built with money earned in Greece, more than half of the 180 families told census officials that, despite their Muslim Albanian names, they are Greek.
Many complain the interviewers simply ignored them, while nationalists accuse them of trying to gain special minority benefits, or worse, aiming to sow ethnic strife.
In the Balkans -- a patchwork of ethnicities, disputed borders and rival histories -- identity can be a dangerous thing.
Up and down the region this year, countries bidding to join the European Union are holding population counts that elsewhere would be a simple matter of mathematics -- key to accurate national data, government spending plans and minority rights.
In the Balkans, much of it scarred by the ethnic cleansing of the 1990s during the collapse of Yugoslavia, they are opening old wounds and stirring controversy as rival groups vie for rights, influence and government jobs.
Macedonia last week abandoned its own census in a row over who should be counted.
Ethnic Albanians, who officially make up 25 percent of the population but say they account for more, complained the authorities were trying to bend the rules to keep their number down.
In Macedonia, the figures should help determine the make-up of the delicate power-sharing balance in place since the country narrowly avoided civil war in 2001 in fighting between government forces and ethnic Albanian guerrillas seeking greater rights.
In Kosovo earlier in the year, the census process was marred by a partial boycott by Serbs who reject the majority Albanian country's 2008 declaration of independence from Serbia.
In Serbia, most ethnic Albanians in the south -- where Western diplomacy also helped end an insurgency in 2001 -- refused to take part in protest at the lack of Albanian-language questionnaires.
And in Bosnia, where ethnic coexistence under Tito's socialist Yugoslavia collapsed in war in 1992-95, Muslim, Serb and Croat communities have been unable to agree on how to hold their own count.
Bosnia's last census was in 1991, before the war killed an estimated 100,000 people and displaced around 2 million.
A new count could have ramifications for the unwieldy, highly decentralized system of ethnic power-sharing enshrined in the 1995 Dayton peace accords.
In Albania, ethnicity was taboo under the Stalinist regime of Enver Hoxha.
Now, nationalist critics are up in arms at efforts to provide an accurate picture of Albania's ethnic breakdown, seeing a plot to weaken the state.
Others argue the records are being manipulated by some Albanians trying to gain special benefits or a way to leave Albania for EU member Greece. Albania and Greece have long disagreed on the size of Albania's ethnic Greek population.
"Some artificial Greek minority is going to ask for special status, maybe for a percentage in parliament or government," said Kreshnik Spahiu, deputy head of Albania's Higher Council of Justice, a body chaired by President Bamir Topi to monitor the judiciary.
Spahiu is leader of the Red and Black Alliance, a movement founded by soccer fans and which takes its name from the colors of the Albanian national flag.
The group has denounced the ethnicity section of the national census, and Spahiu warns the results could upset Albania's "good model" of ethnic and religious tolerance.
The alliance, whose members last week unveiled a huge flag of what they call the Ethnic Albania of 1912 before the Great Powers approved the country's current borders, has appealed to Albanians to boycott the ethnicity question and render the calculation impossible.
"I believe that this registration has the ultimate aim of turning Albania into another Lebanon," where sectarian tensions still simmer after the country's 1975-1990 civil war, said historian and former Albanian foreign minister Pellumb Xhufi.
In Shengjergj, Stela Mustafaj rejected the charge.
She insisted her family took refuge in Albania after the Italian invasion of Greece during World War Two, but was prevented from returning when Albania's isolationist regime closed the borders.
Mustafaj conceded, however, that there was also a financial motive.
"Those who have everything should not forget that our children are out of work," she said. "We want our children to get long visas and go to work there (in Greece)."
Outside the Greek consulate in Korce, there are queues to apply for 100-day visas, and many of those waiting said they hoped to obtain longer-term work permits despite the economic strife in Albania's southern neighbor.
The Greek consul, Theodoros Ikonomou Kamarinos, attracted attention in February when he said people who think they are of Greek ethnic origin should say so on the census and not hide it for fear of a backlash from nationalists.
"I wouldn't say that I agree with certain voices within Albania, which do not make the process of friendship between Albania and its neighbors any easier," he told Reuters last week.