This dumb idea blew up in her face.

A college dropout spent an entire school year convincing her mom she was still enrolled to keep collecting her tuition money — and even invited the family to Graduation Day to keep the ruse alive.

Danielle Shea, 22, wore a cap and gown for the big day at Quinnipiac University in Hamden, Conn., and arrived at the outdoor ceremony with the beaming grads.

But Shea, of Quincy, Mass., was not prepared to be told in front of her mom and other relatives that she was not on the ticket list — and in an act of complete desperation, she stepped away and phoned in two bomb threats to shut the whole thing down, cops said.

“She panicked,” Hamden Police Capt. Ron Smith said. “The mother started questioning school officials, and they said she was not enrolled.”

Shea allegedly used her own cellphone to call in the first threat at around 5:45 p.m. on Sunday, telling police there was a “bomb in the library” near the campus quad.

“After 17 minutes had passed and she didn’t see anyone evacuating, she called in another bomb threat,” Smith said.

In the second call, she warned that “several bombs are on campus” and said: “You haven’t cleared out graduation. That’s not a good idea.”

No devices were found, but the graduates were moved to the TD Bank Sports Center a mile away as a precaution.

Cops traced the calls to Shea’s phone and found her at the arena.

Shea immediately confessed, telling cops that there were no bombs and that she was embarrassed about being exposed in front of her family, Smith said.

She was arraigned Monday in Superior Court in Meriden on charges of first-degree threatening and falsely reporting an incident.

Judge Philip Scarpellino said Shea had spent an entire year “hoodwinking” people, adding, “I’m understanding that the whole year was a lie.”

He set a $10,000 bond even though prosecutors had not asked for bail, and her family put the money up to get her out.

“No comment,” her mom said as she shielded her daughter.

Shea had been a student at the private college — where tuition, room and board top $55,000 a year — until May 2013, spokesman John Morgan confirmed.

She had even made dean’s list.

But she left before the current school year started because she had a debt she couldn’t pay, sources said.

“She was living in Hamden, and she was working, trying to save money for her senior year,” Smith said.

“Her mother was sending her money that she believed was for tuition. What she was doing with that money, I don’t know.”

Her mother was “shocked, in total shock,” he added.

The threats delayed the start of the ceremony for the College of Arts and Sciences by an hour and a half.

Morgan said the delay caused a “major disruption. People had to get in their cars and drive up [to the athletic arena], but they did it very calmly.”