I think most 7-year-old girls these days have at least some idea that boys are different from them, but I was very naive and was raised by my mother and an aunt so in 7 short years I didn't learn about the penis and vagina difference.
When I was about 7, I had this friend named Mark. Mark was 8-year- old and we always said that we were brother and sister.
One day he finally came over to spend the night at my house. The whole night was innocent; there wasn't any, 'you show me yours, I'll show you mine' type of thing that went on.
The next morning, we were eating breakfast early because Mark had to get home to do something with his family. Mark and I were sitting at the table eating and talking but when he got up his erection was making a 'tent' in his pajamas. I reached out and grabbed it to see what he had in his pants because believe it or not, it never crossed my mind that he and I looked different from each other 'down there'.
When I grabbed it, he said, 'hey, stop it!' My mom was shocked and yelled out my name. My mother was angry with me, and so was Mark but I honestly didn't know why.
After we took Mark home, my mom asked me why I would try to touch Mark on his private part. I told my mom that I didn't try to grab his private part but that he had something sticking out of his pants. My mom said that we were going to have a talk when we got home and we did. She said something like this, 'When Mark or any other boy uses the bathroom they have a body part called a penis and that is how their pee-pee comes out.' My mom then found a book with a drawing of a penis and told me that it was what Mark used the toilet with. My mom said that as I got older I would understand why boys and girls had to be made differently.
Mark was mad at me for a long time but when we became friends again I got to see Mark's penis when I spent the night at his house and he was getting undressed for the shower. Then I knew for sure that boy and girl differences were not just in the type of games they liked to play.