To me it seems that at those ages girls are more interested and curious about it. They really push hard to act more grown up. I don't ever see boys respond to the advances. I know when I was those ages some of the girls wanted to kiss and play married etc with me. Sometimes I played along, but I was always more interested in playing tag or games. I just followed along sometimes because I was friends with the girls. A shame now. By the time I wanted to play those games most of the girls did not.