Some House Democrats are concerned about recently crowned rising star Alexandra Ocasio-Cortez, warning the young democratic socialist is making "enemies" of fellow party members before even reaching Congress and showing a "lack of maturity."

Ocasio-Cortez stunned the political world last month with her upset primary win over Rep. Joe Crowley (D., N.Y.), the powerful head of the House Democratic Caucus, in New York's 14th Congressional District. She ran to his left, campaigning on free public college, abolishing Immigrations and Customs Enforcement, and a federal jobs guarantee, and she wound up winning easily in a low-turnout race.

Virtually anonymous nationally before the victory, she's become a political powerhouse in the weeks since, making national television appearances and becoming an in-demand campaigner for other Democrats.

She's also ruffled feathers, The Hill reports, particularly with her accusation against Crowley of not truly supporting her candidacy after he conceded the primary to her on June 26. She angrily accused him of mounting a third-party challenge against her because he was still listed on ballot as the nominee of the Working Families Party. Crowley replied he is not running any active campaign to beat her; his name remaining on the ballot is due to convoluted New York election laws.

"She’s carrying on and she ain’t gonna make friends that way," said Rep. Bill Pascrell (D., N.J.). "Joe conceded, wished her well, said he would support her … so she doesn’t know what the hell she’s talking about."

"She’s not asking my advice," he added, "[but] I would do it differently, rather than make enemies of people."

According to The Hill, when asked if those enemies included Democrats, Pascrell said, "Yes. No doubt about it."

Rep. Lacy Clay (D., Mo.) denounced her for being "petty."

"Once an election is over and you win, why are you still angry?" he said. "I think it’s a lack of maturity on her part, and a lack of political acumen, for her to be that petty. We as Democrats better figure out who the real enemy is. And it’s not each other."

Ocasio-Cortez also has annoyed Democrats with reports of wanting to create a left-wing version of the House Freedom Caucus once she's in Congress—her November victory in the heavily Democratic district is virtually assured given the reliably Democratic electorate in the 14th District. The group would be a sub-caucus of hardline progressives that could influence vote outcomes if Congress is divided relatively evenly between Republicans and Democrats.

Rep. Alcee Hastings (D., Fla.) warned Ocasio-Cortez against alienating senior members of the party before she got into Congress and started forging relationships.

"Meteors fizz out," Hastings said. "What she will learn in this institution is that it’s glacial to begin with, and therefore no matter how far you rise, that’s just how far you will ultimately get your comeuppance."

Her spat with Crowley is not the only time Ocasio-Cortez has tripped up since her primary win. In a Friday interview, she stumbled badly on a question about Israel, remarked unemployment is low because "everyone has two jobs," and said capitalism will one day end.