I might have just accidentally ruined my daughters life

My (38M) wife (37F) and I had PIV sex with her on the middle day of her period. I came inside her, and she’s taking birth control, so we weren’t too worried that she would get pregnant. <br><br>Then today, we’re cooking in the kitchen. My son (15M) and daughter (17F) are sitting at the kitchen table doing their homework. My wife was talking about how she got pregnant with our son the first month that we tried for kids. <br><br>My daughter was shocked. She said “Wait, what? You tried to have kids with your parents? I thought you were an accident!”<br><br>I immediately knew where this was going. I grabbed our son’s arm and told him it was time for dinner, and we left into the other room. My daughter started screaming and crying and wailing. We left and sat in the car to talk about it. <br><br>She started crying harder and saying “I KNEW IT I KNEW IT!!” <br><br>I asked her what she meant, and she just repeated “I knew it!” <br><br>Am I just overreacting? Is it that bad that our kids are siblings?