Elizabeth Warren chose the final day of 2018 to announce her interest in running for president in 2020. She's among the first to enter what's expected to be a crowded race.

A new exploratory committee allows her to start raising money, hire staff and travel to early primary states. It also makes her the first U.S. senator and first woman to take official steps toward a 2020 campaign that could eventually include nearly two dozen contenders. At least seven other senators, current and former mayors, governors, cabinet secretaries and former vice president Joe Biden are considering bids.

The 69-year-old just won her second Senate term in November. She represents Massachusetts, but was born and raised in Oklahoma. Warren taught at law schools in New Jersey, Texas and Pennsylvania before ending up at Harvard University.

With a background in bankruptcy and commercial law, she pushed for the creation of the Consumer Financial Protection Bureau in response to the 2008 economic collapse. In the Senate, she's been a fierce critic of top corporate executives.

In September, Warren revealed a DNA test had found she has Native American ancestors. But the Cherokee Nation tribe denounced her move as "inappropriate and wrong." On Monday, she defended her decision.

"I have put it all out there," she said.

Warren took the test partly in response to attacks by President Trump, who often mocks her.

With 673 days to go until Election Day, other contenders are spending the final hours of 2018 talking it over with their families and interviewing potential staffers. More announcements are expected shortly after the new year.