Eileen Macken said she had never been happier.
She grew up in the Bethany Home orphanage in Dublin and has spent most of her life looking for her birth mother.
A genealogist tracked her down in Scotland.
Ms Macken told RTE Radio 1's Liveline programme: "Once I heard that, nothing would stop me trying to get to see her."
She recalled: "I went over to see her and she's the most beautiful lady, lovely family, they gave me a great welcome.
"We came in and, honestly, I haven't got over the acceptance that I got.
"They accepted me and I had a great chat with my mother."
The Bethany mother and baby home in Dublin has been one of a number scrutinised by an Irish government-appointed Commission of Investigation.
Mother and baby homes were generally institutions where women who became pregnant outside marriage gave birth.
In the main, these babies were adopted.
Bethany was run by Protestant clergy.
Ms Macken travelled to Scotland with her family to meet Elizabeth, who celebrates turning 104 on Saturday.
The mother of three also discovered after meeting her mother that she has two half-brothers.
When she knocked on the door, she was met by a man who turned out to be her half-brother.
She told Liveline: "I told him I was from Ireland and that I had found my mum here and could we come in to see her, and he said, 'Certainly'."
Ms Macken had a "great chat" with her mother during her three-day trip.
She said: "She was reading the newspaper and when she saw me, I said we were from Ireland and she said, 'I was born in Ireland'.
"She was thrilled and she never let go of my hand."
Ms Macken added: "I don't think I'll ever come down out of the cloud."