Jocelyn McKay is now 81 and said she feels “released” from the feelings that gripped her for so long.
“I may be old, but at least I am happy,” she told BBC News NI.
“I hadn’t really lived until I got the operation.’
“For years I felt I was in the wrong body and it wasn’t until I was 69 that I plucked up the courage to ask for help.”
It was only after a trip to Manchester with some friends, during which Ms McKay lived as a woman, that she realised the surgery was something she needed.
“I was a cross-dresser, I went away dressed as a man and I came home dressed as a man, but in between times I was a woman,” she said.
But cross-dressing was not good enough for her.
When Ms McKay returned from her trip, she visited her GP, who referred her to a specialist.
She said: “I had been going to the doctor for a range of ailments and he said to me: ‘Thank God you’ve finally told me what’s wrong.'”
Every week three or four people present themselves as transgender to the Regional Gender Identity and Psychosexual Service at Knockbracken in Belfast.
They typically make contact with the clinic through a GP referral or a drop-in facility every week.
200 people are currently being treated by the clinic with 50 more on the waiting list.
More than half of them are aged between 18 and 25.
The number of adults going to the clinic is doubling year on year.
The clinic provides adults with assessment, psychological support and onward referral for hormone replacement therapy and surgery where appropriate.
A gender identity panel to strategically look at the issues facing transgender people met for the first time at Stormont on Monday.
It was formed by the peer support group Focus – The Identity Trust.
It comprises politicians from Sinn Féin and the Alliance party, as well as a Presbyterian minister, the Reverend Lesley Carroll, and others with a long-standing interest in human rights.
The Sinn Féin minister Megan Fearon said the gathering was about “bringing marginalised people together, giving them space to discuss transgender issues and engaging with politicians in a way that had not been done before”.
“Transgender people still experience discrimination in nearly every walk of life,” she said.
The panel will address trans-phobic hate crime and access to health and education.