A talented student who came within hours of being removed from the UK has said she is desperate to get back to her studies to catch up with the work she has missed while being held in police cells and an immigration detention centre.

Shiromini Satkunarajah, 20, who was about to be put on a plane to her country of birth, Sri Lanka, told the Guardian she could not wait to get home to Bangor in north Wales, where she is expected to achieve a first-class degree.

She thanked the tens of thousands of people who backed her campaign to stay, including fellow students across the UK, academics, church leaders and politicians.

“I feel great,” she said. “The only thing in my head now is to get back to uni as soon as possible and do my assignments. I haven’t finished the practical side of my dissertation yet and my deadlines are coming up pretty soon. I have to catch up with loads of work. My priority is to get back and catch up.”

Satkunarajah, who has been in the UK since she was 12, and her mother, Roshani, were arrested last week after being told their application for asylum had been turned down. They were taken to Yarl’s Wood immigration removal centre in Bedfordshire and were braced to be put on a plane leaving from Manchester on Tuesday evening.

Late on Monday night, the Home Office’s command and control unit confirmed the removal had been deferred and Satkunarajah, who studies electrical engineering at Bangor University, and her mother were freed.

The decision came after a campaign with more than 140,000 people signing a petition, which calling for Satkunarajah and her mother to be allowed to stay.

However, it remains unclear what happens next for Satkunarajah, who is due to graduate in three months’ time. Her legal team will write to the Home Office on Tuesday setting out why it believes her and her mother should be allowed to stay. The government will have 14 days to decide whether to press ahead and remove both women. If that happens, her lawyers are likely to seek a judicial review.

She said she had not thought about her long-term future. “My priority is to stay until I finish my degree. I haven’t had a chance to think about anything yet. I would not like to comment on what happens after I’ve studied.”

Satkunarajah also declined to talk about her treatment at the hands of the Home Office. “My priority is to get on with my studies. I need time to think and get back to my normal life,” she said.

She said she and her mother were arrested on 21 February and told they would have to leave the UK. “We were handed the refusal letter, which states: ‘You do not have a right to appeal or administrative review against the decision to refuse your application.’

“We were taken home straight away to pack a bag and taken to Caernarfon police station. My mother and I were separated and put into two cells.” They were then moved to Yarl’s Wood.

“When I was in Yarl’s Wood there was no time to think. I have to reflect on it to know what’s going on in my mind. It was so much of a shock. I didn’t know what was going on outside. The priority was talking to solicitors. So much was going on. I didn’t have time to think how I was feeling – that was not my priority. My priority was to do something about it. “

When the Guardian spoke to Satkunarajah she was at a cousin’s home in Staffordshire, still trying to make her way home.

“I’m looking forward to getting back home to have some rest. I’m very grateful to every single person who has supported me. This would not have been possible without everyone’s help. It means a lot to me. I am very grateful. I will be forever. Thanks is a very small word to use, but I don’t know what else I can say.”

Her lawyer, Raja Uruthiravinayagan, of Duncan Lewis Solicitors, said: “It appears that these positive developments came about only because this case has seen a groundswell of public opinion and made a clarion call to the secretary of state. We hope that the secretary of state has not taken these steps with the view to temporarily assuage public outrage.

“We are inviting the secretary of state to restore a modicum of justice and fairness in our broken system and grant our client and her mother a more stable form of leave to remain in the United Kingdom on a long-term basis.

“We hope that there will not be prolonged litigation in this case during the period when Shiromini is studying.”

The student’s MP, Plaid Cymru’s Hywel Williams, who has campaigned for her to be allowed to stay, said: “This is the news we’ve all been hoping for. I’m so very glad that Shiromini and her mum have had this deportation order rescinded and [have been] released from the detention centre. I’d like to thank everyone who backed the campaign to have the deportation order lifted. So much has been achieved in so little time.

“The outpouring of support from across the country has been staggering, particularly from north Wales where Shiromini is highly regarded within the Bangor community. Sri Lanka is still a very dangerous place and Shiromini has had no real ties with the country since she was a child.

“Of course, the campaign to right this unjust situation is not over. There is clearly something seriously wrong with the current system and it is an issue I intend to pursue.”

Satkunarajah has lived in the UK since for eight years after her parents fled the Sri Lankan civil war. Her father, who had a student visa, died in 2011. She was given leave to complete her secondary education, but an application by her and her mother for asylum was denied, triggering the removal process.

Among those who urged the Home Office to let her stay was Bangor University’s vice-chancellor, John Hughes. The university said: “Our view is that it would be in the best interests of the student that she be allowed to complete her studies.”

Iestyn Pierce, the head of the school of electronic engineering at Bangor, said Satkunarajah was an “exceptionally able and diligent” student, adding: “If allowed to graduate, Shiromini would be sure to be a valuable member of the workforce in what is a worldwide shortage subject. Undoubtedly, if allowed to continue her studies, she can contribute to society in areas such as low-carbon energy, communications and environmental technologies.”

Pete Broadbent, the acting bishop of London, said: “To deport her weeks before she completes her degree and to remove her from the community that supports her seems draconian.”