My dad said that I was a 'mistake'!?

I'm 16 years old. My mother died when she hemorrhaged after giving birth to me. So i never knew her. I don't really have any other family, so I got stuck with my dad talking to me about 'girl' stuff. Yeah, it's been more than awkward. My dad is 33. He and my mom had me really young, they were in love and all. But yesterday. my dad decided to tell me about sex... weirdest moment of my life. But the worst part was when he said, 'I hope you wait until you are married, then you won't make the mistake your mom and I made.' He said 'mistake', not even plural! What or WHO else could he be talking about? I love my dad, and it makes me sad to know that I ruined his life. I mean, I'm the 'mistake' that killed the love of his life... I'll never forgive myself.