Senator Dianne Feinstein confirmed for reporters Monday that she will be running for her fifth term in the Senate next year, and she is "all in."

As the Associated Press notes, Feinstein is now the oldest US Senator, at age 84, and she will be turning 85 in June, but she shows no signs of wanting to slow down or kick back and retire. In a post on Facebook she writes, "I’m immensely proud of my service in the Senate and all I’ve done to help the people of California and the nation. But there’s still so much work left to do, from ending gun violence, to combating climate change, to ensuring proper and affordable access to healthcare, and to giving DREAMers the chance to stay in the United States."

The announcement comes as no surprise given Feinstein's personality, and despite her needing to take a few days off in January to have a pacemaker installed. Though speculation has swirled that she might leave a vacant California seat up for grabs next year, possibly to be taken by a Republican like Arnold Schwarzenegger.

NBC News suggests that Feinstein's perseverance might be "setting the stage for a potential Democratic battle in the heartland of progressivism." And that could mean a more expensive reelection effort than Feinstein has had to deal with in decades.

But NBC also notes that in such a large and diverse state, it can be difficult for candidates with no name recognition to break through, and the "the 'jungle primary' system, in which the top two candidates, regardless of party, advance to the general election, is designed to have a moderating influence, which could help protect Feinstein."

Feinstein's comrade in the Senate Barbara Boxer, who was elected, as she was, in the early '90s, decided to retire last year, however as we know, Boxer has a second career as a novelist (with ghostwriting help) to turn to.

Previously: Sen. Dianne Feinstein Says Daughter Was Supposed To Go To Las Vegas Music Festival