Critics lamenting the possible return of the PRI to power aren't thinking straight, she said.
"That's all in the past. What's important is that he is young and has all the ability to represent us," she said.
Alejandro Garcia, a 33-year-old accountant, said he supported Peña Nieto's security strategy, which aims to decrease violence in Mexico.
Calderon, Mexico's current president, made combating cartels a top priority when he took office in December 2006. Since then, more than 47,500 people have died in drug-related violence nationwide, according to government statistics.
Garcia said the surge in violence has negatively impacted daily life throughout the country.
"People don't go out as much in the streets. People go inside their homes earlier in the day. ... Now we are seeing things that we didn't see before. Maybe they were going on, but they weren't as open as they are now," he said. "I think (Peña Nieto) is the one to stabilize the country."
Other voters were less decisive about their choices.
"We are voting for the least bad candidate," said Manuel Palomera, a 34-year-old travel agent who said he was casting his ballot for Vazquez Mota.
At one polling station in Mexico City, a 46-year-old attorney from the state of Michoacan was fuming. Thalia Vasquez was one of hundreds of out-of-town voters who went to a special polling place to vote and had to wait for hours.
Shouting matches ensued when people tried to cut in line, she said.
"Imagine how long this is going to take," she said, saying election authorities should do more to monitor the lines outside the polls.
Voters still in line after polls close at 6 p.m. were allowed to vote, election officials said.
Mexicans also cast ballots from beyond the country's borders. On Saturday, election officials said they had received 40,737 absentee ballots from Mexicans living abroad.
For the first time, more than 79 million people were registered to vote, according to election authorities. Among them are 3.5 million young people who will be casting their first vote, the institute said.
More than 2,100 federal, state and local offices will also be decided by Sunday's vote, according to Mexico's Federal Election Institute.
Voters will elect governors in the states of Chiapas, Guanajuato, Jalisco, Morelos, Tabasco and Yucatan. In Mexico City, the nation's capital, residents will elect a new mayor.
Election authorities suspended voting an hour early at nine polls in the southern state of Chiapas Sunday after clashes between political groups backing competing candidates for mayor in the town of Rincon Chamula. Several people were injured, the Federal Election Institute said.