It sounds like she has definitely made up her mind on this.

During what is being called 'a landmark speech' in Florence today, British prime Minister Theresa May marked out the future of the UK in terms of the impending Brexit and the future of her government's dealings with the rest of the EU. Over the course of her 35-minute speech, the British PM stated that neither the UK Government nor the EU would be ready to fully implement new arrangements for Brexit on 29 March 2019, when the UK is scheduled to formally leave, stating that "As of today (22 September), these considerations point to an implementation period of around two years." The topic of the border between the UK and the Republic Of Ireland was also brought up, with May sounding particularly firm against the idea of a physical border being put in place: "We will protect progress made in Northern Ireland over recent years. We and the EU have committed to protecting the Belfast Agreement and the Common Travel Area." "We have both stated explicitly that we will not accept any physical infrastructure at the border. We owe it to the people of Northern Ireland and to everyone on the island of Ireland to see through these commitments."