TAMPA, Florida — America's Grand Old Party, meet your Generation Next -- a fresh-faced crop of 30- and 40-something Republicans led by VP pick Paul Ryan who buzz with youthful energy as they shake up the party establishment.

While homage has been paid to the party's elder statesmen at the Republican National Convention, and the delegates themselves appear largely middle-age or older, the conservative jamboree is showcasing several rising stars that may soon rule party.

Key among them is 42-year-old Ryan, who made the convention and millions of Americans watching in living rooms perhaps painfully aware of how he was "a full generation apart" from the man at the top of the ticket: 65-year-old Mitt Romney.

"I accept the calling of my generation to give our children the America that was given to us, with opportunity for the young and security for the old," he said Wednesday in a prime-time address.

Romney listens to elevator music, Ryan joked. "I hope it is not a deal-breaker Mitt, but my playlist starts with AC/DC and it ends with Zeppelin."

Was Ryan openly signaling that a new day was dawning among the Republican leadership? Perhaps, but delegates and lawmakers at the convention were optimistic that the generational shift is good news for a party that has long struggled to attract younger voters.

Democrat Barack Obama was elected president at age 47, and Bill Clinton was a year younger when he won the White House. Republicans are out to prove that their rivals haven't cornered the market on youthful politicians.

"Of course it's very exciting," conservative Florida congressman Allen West, who was 49 when he became a first-term lawmaker early last year, told AFP about the injection of new blood into Republican politics.

"Here's Paul Ryan, a generation away from the presidential candidate he's running with," West added. "That represents a path forward for our future."

That future was embodied in speakers like Governor Nikki Haley of South Carolina, 40, and Mia Love, the mayor of Saratoga Springs, Utah who was born way back in 1975.

Love is seeking to become the first black Republican female elected to Congress, in November, and she received a hero's welcome when she took the stage.

"It's a very exciting transformation," said US Senate candidate Ted Cruz, who at 41 would be the third youngest member of the chamber.

"It has a produced a new generation of leaders in the Republican Party," he told USA Today newspaper.

That group includes Bobby Jindal, 41, the governor of Louisiana, and House Majority Leader Eric Cantor, 49, who along with Ryan is one of the self-proclaimed "young-guns" in the House.

And of course there is Cuban-American Florida Senator Marco Rubio, 41, who will push his humble family story -- one shared by countless young immigrants -- as he introduces Romney on Thursday night.

Rubio said his own parents "emigrated to America with little more than the hope of a better life," taking jobs like bartender, cashier and stock clerk at K-Mart.

"They never made it big. They were never rich," he added. "And yet they were successful. Because just a few decades removed from hopelessness, they made possible for us all the things that had been impossible for them."

Nearly all these young Republicans embrace the fiscally conservative trifecta of lower spending, taxes and deficits.

The 40-something with some of the greatest political star power is blunt-talking New Jersey Governor Chris Christie, who received a rock-star welcome when he gave the keynote speech Tuesday after Ann Romney.

The voluble Christie, who was considered a long-shot potential running mate for Romney, praised the candidate, but he also sounded like he was auditioning his own 2016 presidential bid.

By all accounts he'll have some competition from older rivals like 59-year-old ex-Florida governor Jeb Bush, brother of former president George W. Bush; Mitch Daniels, 63, the former Indiana governor whom many pressed to run for president this year; and 2008 candidate Mike Huckabee, 57.

While many in that generation served in Vietnam or sought to avoid the draft, several of the country's new lawmakers weren't even born until after the end of the Vietnam War.

At 31, Aaron Schock is the youngest person in Congress -- although four years older than Ryan when he came to the House -- and one of just two born in the 1980s.

"It's no secret that the Republican Party has struggled in the past years to reach this demographic," he told AFP.

But that could be changing. In 2010, voters swept out much of the old guard, electing a massive 86 new congressmen, "40 of whom had never run for office of any kind," Schock said.

"I think it speaks to this groundswell, this grassroots movement among the American people that we need to kind of change some of the bureaucrats out in DC, some of the lifetime politicians... with some younger, fresher perspectives."