Watch Maryland gubernatorial hopeful Heather Mizeur in her first television ad ahead of the June 24 primary. (Delegate Heather R. Mizeur)

Months after political ads first started hitting the Maryland airwaves, gubernatorial hopeful Del. Heather R. Mizeur (D-Montgomery) has collected enough money to join her rivals. With less than a month until the June 24 primary, the Mizeur campaign plans to start broadcasting an ad in the Baltimore area on Tuesday.

Mizeur’s opponents — Lt. Gov. Anthony G. Brown and Attorney General Douglas F. Gansler — shifted to negative attacks on one another in their television ads this week. But Mizeur opted for a commercial that highlights her childhood experience of walking a picket line with her father, a factory welder, and her record in the Maryland House of Delegates, including sponsoring legislation to enroll more children in health coverage.

The ad — titled “Walking” — opens with weathered footage of a picket line, as Mizeur narrates: “Standing up for what you believe in takes courage. Walking a picket line with my dad when I was 9 years old, I learned the importance of fighting for what’s right.”

The 30-second ad also touts Mizeur as “the only progressive with a plan for good jobs and stronger schools, paid for with revenue from the responsible regulation of marijuana” — which most would instead call legalizing pot.

“We’re not running to make history,” Mizeur says at the end of the ad, standing on a shop-lined street with her running mate, the Rev. Delman Coates. “We’re running to make a real difference in Maryland.”

Heather Mizeur stands in front of her campaign office in Silver Spring. (AP Photo/Brian Witte) (Brian Witte/AP)

If elected, Mizeur would achieve a number of firsts for the deeply blue state: the first woman governor, the first openly gay governor (also a first for the nation) and the first governor from Montgomery County.

Mizeur is participating in the state’s public-financing system, which provides matching funds to candidates who agree to limit overall spending. According to campaign finance reports filed this week, her campaign has about $1 million to spend. That’s much less than Brown ($4.15 million) and Gansler ($3.11 million) have in the bank, but her campaign is convinced that it’s enough to get her message out to voters before the June 24 primary.