Theresa May will return to the UK later to try and convince MPs to support her withdrawal deal after the EU agreed to postpone Brexit beyond 29 March.
On Thursday night, after eight hours of talks, EU leaders offered to delay Brexit until 22 May if MPs approve Mrs May's deal next week.
If they do not approve it, the delay will be shorter - until 12 April - at which point the UK must set out its next steps or leave without a deal.
Mrs May said MPs had a "clear choice".
Speaking on Thursday, after waiting for the 27 other EU countries to make their decision at a summit in Brussels, the prime minister said she would now be "working hard to build support for getting the deal through".
MPs are expected to vote for a third time on the Brexit withdrawal deal next week, despite speaker John Bercow throwing the process into doubt.
Giving a news conference, Mrs May also referred to her speech from Downing Street the previous evening, which sparked an angry reaction from MPs after she blamed them for the Brexit deadlock.
"Last night I expressed my frustration and I know that MPs are frustrated too," she said. "They have difficult jobs to do.
"I hope that we can all agree we are now at the moment of decision. And I will make every effort to ensure that we are able to leave with a deal and move our country forward."
BBC political editor Laura Kuenssberg said Mrs May, although she did not apologise, had shown a "very different tone to MPs".
But she added that the PM was not drawn on what she would do if her deal fails again in a vote next week.
A debate on the deal has been scheduled for Monday but Downing Street said no date has yet been fixed for a vote.