The 18-year-olds celebrated their achievement yesterday at Trinity Academy, in Thorne, near Doncaster.
It has been a difficult journey for the twins who were born 11 weeks premature with a series of medical condition including having holes in their hearts.
They struggled throughout primary school and say they fell behind their classmates, who were all reading and writing before them.
But years of hard work and support from teachers have led the high-flying sisters to become the first people in their family to go to university. They will both take up places at Homerton College in the coming academic year to read English literature.
Kirstie said: “Our parents always believed in us. When we visited Cambridge, mum said ‘you’re going to end up here’.”
Zoe added: “Our parents have never been to university and they don’t know much about the process, but they’ve always been so supportive.”
Both twins got A* grades in English and As in religious studies while Zoe got an A* and Kirstie an A in history. Kirstie, meanwhile, also gained a B in French, while her sister scored a C in the same subject.