The 27-year-old pop star had not been in a relationship nor had she been physically intimate with anyone until she met dating expert Matthew Hussey, now 36, and recalled that even though she was "late" in having her first boyfriend, everything was "beautiful" in the end.
Speaking on the 'Armchair Expert' podcast, she told host Dax Shepard: "I had my first relationship at that time. I was outside ['The Today Show' studios] where they had the TV with the scripts. I had actually listened to his podcast before ... because he had, like, a dating podcast. And he is married now, so congratulations.
"We went to dinner that night and that was my first relationship. It was late for my first relationship. I was 20. That was my first time having sex. "First lovemaking was at 20, 21. ... It was literally lovemaking. It was beautiful."
The 'Havana' hitmaker split up from Matthew - who is now married to Audrey Le Strat - in 2019 after just over a year of dating but she was still keen to speak positively of him as she noted that he had taught her a lot in those early days, especially because they were in different industries.
She said: "But I think that also honestly made him a great partner. He was a really great person. It was like the perfect first relationship. It really expanded my world because he wasn't in my industry too.
"It was like, 'Oh my God, have you ever seen Anthony Bourdain: Parts Unknown and have you ever seen Studio Ghibli films?' He just really expanded my references."