My child passed her 1st birthday. she still not walking not sit unassisted. she go here and there very little with her back. other things are ok. ?

Time for consultatn: Kids may not walk independently until 15 months or so.However, if she does not have a stable upright sitting posture by now she is delayed. Significant prematurity would shift expectations some, but this is something you should review with her doc.

Scooting around on : her back by arching means there is an imbalance in the strength & tone of her extenstor muscles vs. her flexor muscles. The cause is often from atypical development of or injury to the brain or central nervous system during fetal development. Her pediatrician may order an MRI of the brain & other studies & refer her to a pediatric neurologist & physical therapist after clinical evaluation.