Hillary Clinton said in a new interview that using a private email server as secretary of state "wasn't the best choice," but that she did not "stop and think" about it. 

In a sit-down with NBC News' Andrea Mitchell, Clinton recalled that when she began at the State Department in 2009, there were more important issues to be dealt with. 

"I was not thinking a lot when I got in. There was so much work to be done. We had so many problems around the world. I didn't really stop and think, 'what kind of email system will there be?'" said Clinton. 

She added that she takes responsibility for the decision, apologizing for the "confusion" over the email server, though she did not say she's sorry for using it. Clinton said that looking back, she wishes she would have "made a different choice."

Mitchell brought up a recent poll in which voters were asked for one word that comes to mind when they think of Clinton. The word "liar" was the top response. 

"It certainly doesn't make me feel good," the former First Lady told Mitchell. "But I am very confident that by the time this campaign has run its course, people will know that what I've been saying is accurate." 

Clinton has maintained that she never sent or received classified information via private email.

Her comments come one day after a former Clinton aide told congressional committees that he will invoke the Fifth Amendment to avoid having to answer questions about the emails. 

Bryan Pagliano worked on Clinton's 2008 presidential campaign before helping install her private server in her New York home.

Watch Ed Henry's latest report from Puerto Rico on the Clinton campaign trail.