When's the right time?

Hannah
So I'm 18 and little does my mother know that I've had sex. I lost it about a year ago to a boy whom my mother didn't like and didn't know I was seeing and he treated me like crap.. But I have learned from my mistakes and have been dating a boy who treats me like a queen for the past, almost 2, months. He and I recently began having sex and I want to be open and talk to my mom about it but I'm not sure how to break the news.. And I don't want her to be disappointed in my previous sophomoric actions. I feel as though I'm responsible enough and can handle all the stuff that comes with sex, but I just don't know how to tell her. Did you tell your parents you were having sex? How old were you and how did they find out? Thanks so much