Did I mess up by telling my friend to erase those voice notes?

Salaam, I need some advice. A close friend of mine mentioned that she recently got a ride to uni with a male classmate. She’s currently getting to know a brother for marriage, and she sent him voice messages explaining that she came to campus with that classmate. I told her straight up that, Islamically, I don’t think that was a good move in the first place. She agreed and said she felt bad about it. Then I suggested she delete those voice notes. Not to hide the truth, but because I’ve always heard that in Islam, we shouldn’t go around sharing our sins after we’ve repented or realized we messed up. So my question is: Was I wrong for telling her to delete them? Or does that make sense from an Islamic view? JazakAllah khair.