It is predominantly two syllables per stress, weak-strong, so it is iambic. The refrain is basically dactyllic, with an extra beat at the end, but the narrative part is iambic.
For only this line, Note the pattern of stressed syllables: HICK-o-ry DICK-o-ry DOCK --- that's (principally) dactylic
. She is an adult when telling the story and she is looking back on the memories of her childhood. She is telling the story in 3rd person and since she is older, has a more mature view of what she did when she was younger.
