That’s ridiculous! 15 is young, but certainly not unusual. I don’t know what his problem was. Be glad you’re rid of him because he’s obviously an asshole. I don’t even understand how rumors got started because of THAT. It’s so absurd… He clearly has some issues and they have NOTHING to do with you.
No, it was not wrong of you to have sex when you were 15. As long as it was your choice and it was what you wanted. I do think it’s on the young side and I always advise people to wait a little longer, but you did nothing wrong! Don’t for one second feel ashamed just because some uptight dickwad tried to put you down. It’s your life and your choice and it certainly does not mean that you’re a “whore” or any of that BULLSHIT. You had sex when you were 15. SO WHAT? Who cares? You’re 21 now. It’s all in the past.
You did nothing wrong so please don’t ever let people like that guy (or anyone else) make you feel like you did. They have no right to judge you and you shouldn’t give a shit about what they think (because what they think doesn’t matter).
YOU matter. What YOU think matters. That’s all you have to worry about: you.