"I was born first, and Liz (Palmer) was not mucking around and came three minutes later.
"The doctor assisting said to mum 'hang on a minute, I think there's another one'.
"That was Rose (Toms) - she took a bit longer than us other two because they had no idea she was even there."
Although triplets were rare, the fact that they were identical made it extra special, said Mrs Hortop.
"It was in the air - on the farm identical triplet lambs were born that year."
Their birth on Coronation Day inspired their royal names, and their appearance prompted King George VI to send the family a king's bounty of three pounds (one pound per child) to mark the occasion.
Their first six months were spent at a Karitane home in Wellington, Mrs Hortop said, and for the first year a Karitane nurse was at home with them.
"Mum was a bit sick after the birth and the Government put a special carriage on the train for us to go to Wellington, accompanied by nurses."
Although that was the only government assistance they received, the local community was overwhelmingly generous, she said.
"That's why we say we owe a lot to the kindness of people of Hastings who raised money through card evenings and provided knitting and other clothing."
Local firms also contributed, with the likes of Westerman's and Roach's supplying beds and garments.
Even the editor of the Herald Tribune at the time called on the community to contribute "a bob" towards a larger, custom-made pram that was built for the girls.
"Mum only had a pram for one child - a Hastings firm, A Christie and Sons, made the special pram and that drew people's attention."
The girls thrived on the farm where they were schooled, first by a teacher, and then by their mother before they went on to Parkvale School.
As well as conducting their schooling for a time, their mother - with the help of their four elder siblings - worked hard to take care of them in an era when there were none of today's conveniences.
"We had no power, no fridges - water was boiled in a copper and everything had to be washed by hand.
"I can still see the buttons flying off the clothes going through the wringer.
"All the food was cooked on the coal range - we do not appreciate how hard it was then."
Wherever the trio went in those early days they would be mobbed by people.
"Mum didn't take us into town in the end - she could not walk down the street without someone stopping her, so she would leave us with an aunt in town."
When they were younger the girls wore bangles with their names on to help others tell them apart, but it was still a common occurrence for people to ask the girls which one they were.
"After all these years I got bailed up just the other day and asked which one I was and I said 'take your pick!'"
After they left school and went out to work, the girls happily abandoned the identical clothing, mostly made by their mother, they wore growing up.
"The first thing we did was get rid of those clothes."
They had been too hasty though. On January 20, 1954 Queen Elizabeth visited Hastings and got wind of the triplets and requested to meet them.
By then they had no clothing that was the same so had to rush out and get three matching dresses to wear for when they met the esteemed visitor.
In the ensuing years the sisters had their own families and while Mary lives in Havelock North in a villa at Mary Doyle retirement village, Liz now lives in Summerset in the Bay, while Rose lives on the Sunshine Coast in Australia.
They were all in Hawke's Bay last week in advance of today's party at Riverstones Cafe in the Mary Doyle complex, and to which more than 50 people had been invited.
"We are making this birthday special - the chances of us being together for our 90th birthdays are pretty remote, so we are making the most of it," said Mrs Hortop.