"She couldn't stop talking about it, so we thought, 'right - into it'."
The Taradale family had no prior connection with the world of flight.
"It is a huge thing for the family and Alexandra has an absolute bug for it now. She has worked out what she needs to study at school so she can go on to commercial aviation."
Sunday's epic was her 60th flight in all. Mother Kirstin Thompson said she was ready for the solo flight several weeks ago but weather conditions were not perfect.
Her father said: "She had to get sign-off from three instructors because she's so young - they've all got to be happy she's capable.
"It was her 13th birthday and we were having a bit of a party out at the aero club, so it was really special with her grandparents and godparents there.
"We didn't talk to her before she went off and did her solo - so we didn't get her wound up.
"The biggest thing was there was a 15-minute delay while the tow plane refuelled so she was sitting in the hot seat, knowing she was going to be going solo."
Alexandra said that at 500m the tow plane cut her loose.
"It was a bit scary at first because there was no one to talk to and I had to make my own decisions," she said.
"I was a bit anxious but then all my training kicked in and it was like, I know what I'm doing.
"It was really weird being silent with no one talking to me, and I really didn't want to talk to myself, so I started singing."
On the ground her family were not singing.
"You have no idea how terrifying it was," her mother said.
Grandmother Diane Thompson said: "She disappeared behind a cloud - it was a bit dramatic for me, I must say."
Alexandra circled the field singing for seven minutes, "trying to lose height".
"There is a lot of lift that time of day," Alexandra said.
Her landing had been "spectacular".
"Everything went to plan and it was an amazing speed.
"When I got out of the glider everyone was cheering me on - it was just amazing."
Alexandra's next goal is a licence to fly any glider, followed by powered flight and a career in aviation.
