When I was 12 I had a friend that had a very Hot Mom with big tits. I think she was like 31 at the time. She was the talk of the school with the 4th grade boys. I remember spending the night there a couple times and getting strange sexual feelings. We would get so excited to spend the night there. We used to sit under the door and try to peak under while she was taking a shower.
I think adults tend to forget just how early kids start getting curious about this stuff.