A number of ministers are believed to be trying to persuade the prime minister to delay the vote scheduled for December 11 amid fears she faces a defeat that could bring down the government.
But speaking of BBC Radio 4’s Today programme, Mrs May said was continuing to prepare for the Commons showdown.
"We are in the middle of five days of debate in Parliament which will lead up to a vote on this issue," she said.
It came as the European Court of Justice announced as a ruling on whether the UK can cancel Brexit by revoking Article 50 will take place the day before the vote.
Addressing concerns over the controversial Irish border backstop, the prime minister added: "I recognise that there are those concerns. Any deal, any agreement, any arrangement that we came to with the European Union would involve a backstop.
"So, people talk about, 'let's have a Norway, or let's have a Canada', everything involves a backstop.
"Secondly, none of the other arrangements that people have put forward fully deliver on the referendum. This deal delivers on the referendum."
Mrs May said the backstop element of the deal was an "integral" part of any withdrawal agreement but insisted while there is "no unilateral right" to pull out of the backstop, the UK would have a choice over whether or not to enter into it.
"The backstop is something nobody wants to go into in the first place, and we will be working to make sure that we don't go into it," she said.
"If we get to the point where it might be needed, we have a choice as to what we do, so we don't even have to go into the backstop at that point."
The PM signalled that MPs would decide whether the UK went into a backstop or extended the transition period.
She said she had negotiated a "good deal" that "delivers on the referendum" but refused to be drawn on whether she had a "plan B".
"That question is not for me, that question is for those who say that they want to oppose this deal," she said.