I love the stage when young teens are like a pile of puppies, just before they "grow up". They want contact but not sex, not quite yet.
Tonight, my youngest child, (my daugther), my "other" daughter (her real mom and I both lay claim to both girls since they are together all the time) and a lovely young man spent a wonderful day/evening together. They built a fire, they horsed around, they watched TV and rolled in the leaves, they braided the boy's hair, they cooked, ate and ate some more. All the while maintaining close physical proximity but not quite flirting, more a hyper bouncyness.
The neighborhood kids play/interact/hang around together in multi-age groups until some of the oldest have started high school. The youngest are in nursery school. The older kids may be "watching" the little ones but are also happy for an excuse to play with bubbles, swings, etc. Once dating starts the relationships in the neighborhood change. I've watched this over and over for the last 5 years as my sons and their cohorts "grew up".
Soon, the comfort level with the group will leave and the pair bonding will start. I didn't mind when she left middle school. I don't care that my "baby" is now an official "teenager" but I'll miss the puppy stage.