Understanding angular momentum with swing

Well, not quite. I took Marian out to the park and it was fairly busy. She appeared to be waiting to get on the big children's swing (without the supporting frame) and once it was free, she bounded towards the it. This was a surprise because she has never shown so much interest. I helped her on and I started her off. For the first time she began to move her arms so that she could distribute her weight differently as the swing swung. She did not do it perfectly but when the timing was right, the swing moved so much that I became quite worried (normally I can remain crouched and stretch out my arms at the front and back of the swing but this time I had to be on my toes). I think the eagerness to get on the swing stemmed from the fact that she wanted to try out her newly acquired knowledge. I never really taught her to move her arms (I had been teaching her to move her legs correctly). She must have been slowing absorbing what the other children were doing . Slowly because she never really observed them carefully. The observations were always fleeting.