It’s time for Sen. Kirsten Gillibrand’s sputtering presidential campaign to call it quits, a friend of hers and two former aides told The Post.

“It would be best if she decided that this was not her time,” said one longtime Gillibrand fundraiser, who claimed the Democratic contender’s well-heeled supporters want her to remain in the US Senate.

“Most people that I talk to are very happy with her as their senator and don’t want her to give up her Senate seat and don’t see any realistic traction for her.”

As Gillibrand struggles to get 130,000 individual donors to qualify for the third Democratic debate in Houston next month, it’s unclear if she’s hearing the message from those who have worked with her.

“I don’t know that anyone even wants to see her on the debate stage. Everyone I have talked to finds her performative and obnoxious,” said a former senior staffer in Gillibrand’s Senate office.

“She comes across as an opportunist to the public. I think that’s the biggest problem,” said the staffer, who criticized the candidate’s flip-flopping on guns and immigration. “I think she’ll have to seriously evaluate her campaign and her candidacy if she doesn’t make this debate.”

“She’s not going to make it,” said another longtime friend and supporter. “What is Kirsten’s reason to stay in? She should find some gracious way that enhances her . . . as she gracefully exits and throws her conditional support to whoever does get [the nomination].”

Gillibrand has resorted to hawking T-shirts to anyone willing to chip in $1 to get her on the debate stage.

“Time is running out to get a FREE Gillibrand 2020 t-shirt if you donate $1 toward securing Kirsten’s spot on the September debate stage,” said the candidate in one of several fundraising e-mails this month promoting the offer.

“Offer valid only for supporters who make their first-ever donation to Gillibrand 2020,” she noted in the fine print.

The shirt — a USA-based, union-made, cotton/polyester blend — retails for $30 on the candidate’s campaign store.

So far the Gillibrand campaign has taken in money from roughly 115,000 individual donors and lags well behind lower-tier candidates like Rep. Tulsi Gabbard and Marianne Williamson, both of whom have already blown past the 130,000 mark.