Several young Democrats said they are embracing the "vibe shift" in the party that they've experienced over the last few weeks, feeling newly enlivened at the Democratic National Convention with Vice President Kamala Harris at the top of the ticket.

"I've been around a lot of political things for the past few years, and it has never felt this exciting," Jonah Simon, 20, told ABC News at the DNC.

Simon said he feels that unlike merely a month ago when President Joe Biden was the nominee, younger voters now have a candidate in Harris they are "proud to get behind, somebody who we can be really excited to rally around."

For decades, younger voters were a reliable part of the Democratic coalition, including in the 2020 election. But polls leading up to Biden's departure from the race showed his wide advantage with Americans between the ages of 18 and 29 had diminished.

Liz Benecchi, 22, echoed a refrain heard from Democrats young and old -- that while the party respected Biden's record and decades of service, there was a necessity to turn the page.

"I have so much admiration and so much deep respect for him. I'm going to be honest, I wasn't as excited about going out on Election Day to vote for President Joe Biden. But it was time for something new and it was time for a change. And I think everyone here is really fired up," said Benecchi.

Benecchi pointed to the Harris campaign's fresh embrace of social media, especially TikTok, leaning into memes like "brat summer" and Harris' viral "coconut tree" moment, as a more earnest way to communicate with the party's youngest flank.

"I have so many friends that want to get engaged. They want to volunteer, they want to canvass, they want to be a part of it," Benecchi said.

That kind of enthusiasm can't exist in a vacuum -- and Lorenzo Ruiz, 20, said he feels like the energy transfer to get-out-the-vote mobilization is kicking off in earnest now.

"We're moving on the right path. The trajectory feels like it's toward victory, and we're really seeing people lock in and engage. And that's what we need. We need people excited. We need them happy and joyful. And this is a joyous campaign. And, that's the campaign that we've been building and that we as a group, people on the campaign, people working grassroots, will continue to build. And, I think we're going to win this thing," Ruiz said.

This sort of enthusiasm is reflected in the newest ABC News/Washington Post/Ipsos poll, with the data showing an 18-point swing from Biden (at +2) to Harris (at +20) with people under 40.

But her support from the younger generation is not guaranteed -- especially as young progressives remain heavily critical of Biden's (and Harris') position on Israel.

Jasmine Wynn, 19, one of such progressives, still plans on voting for Harris regardless. And while she acknowledges that others on the left may not follow suit, Wynn supposes that there's a practical argument to be made to persuade them.

"I think a lot of young left, especially my friends, initially they were reluctant to vote for Harris or any kind of like Democratic ticket because of kind of what they've done so far in Gaza. But I think there's kind of a shift in terms of, I think, approaching electoral politics in a very pragmatic sense as opposed to an idealistic sense," said Wynn.