In September, Ayanna Pressley defeated 10-term incumbent Michael Capuano in the Democratic primary for the 7th Congressional District of Massachusetts. Since she will not face a Republican opponent in the midterm elections, Pressley is poised to become the first black woman to represent Massachusetts in Congress.

The upset victory surprised many. When she learned that she had won her race, Pressley herself was taken aback. In a reaction video that has since gone viral, Pressley's eyes widen, she puts a hand on her necklace and asks "We won?"

Pressley reaction.

With her most difficult race behind her, Pressley is gearing up to advocate for her district in Congress.

"While they are certainly exacerbated by the hatred and vitriol coming out of the White House, the challenges facing Massachusetts' 7th district are not new — they have existed for decades," she tells CNBC Make It in a statement. "In Congress, I will be focused on lifting up the voices of those in community, partnering with activists and residents, and ensuring that those closest to the pain are closest to the power, driving and informing the policy-making."

Pressley's victory over Capuano — a staunchly liberal Somerville native who has held his seat in Congress for 20 years — may have come as a surprise to some, but others see Pressley's rise to political power as a long time coming.

Pressley previously worked for Senator John Kerry and Representative Joseph Kennedy II. In 2009, she became the first black woman elected to the Boston City Council. In 2014, she was named one of the 10 Outstanding Young Leaders by the Greater Boston Chamber of Commerce and in 2015, she was named one of Boston Magazine's 50 Most Powerful People. In 2016, she was named one of The New York Times 14 Young Democrats to Watch.

As a Boston City Councilor, Pressley established Boston's Committee on Healthy Women, Families and Communities, updated school district policies for pregnant and parenting students and developed sexual education and health curriculum that is now a permanent part of Boston Public Schools' wellness policy. She supports universal healthcare, gun reform and the abolition of Immigration and Customs Enforcement (ICE).

Many have compared Pressley's victory to that of Alexandria Ocasio-Cortez, the 28-year-old political newcomer who beat leading House Democrat Joe Crowley in the Democratic primary for the 14th Congressional District of New York in June. Ocasio-Cortez is set to become the youngest woman ever elected to Congress.