When I was 16 I met this also 16 yo girl from a very small town on the countryside. She was very naive, would speak with a very funny accent and was very innocent. She came to study in my school. Everyone on school would make fun of her, so I approached her to be her friend. Then we started dating and one thing led to the other, she said she was ready. Here's the confession proper: I told her that sex was done anally, and "took her virginity". We dated for quite a long time (~18 months) until she found out the truth. But being so naive, I told her that I didn't actually know the truth, and she believed me. We're 22 now and still on a relationship.