Autism symptoms

Hey mamas! I have 15 months old twins boy/girl My daughter is very smiley girl she does clapping waves bye and hi. Blowing kiss, says no no. Says dada nana before she said mama now she says nana for some reason. Sometimes she started to ignore she is not responding to her name sometimes My son is responds to his name well when I am calling to come he comes eye contact is perfect smiles and only gesture he does is he puts his one and to his ear and says hello. He gives his toy when I’m Asking or playing with ball but No other gestures. But he says mama dada give baby Is it could be an autistic sypmtoms? My daughter not walking yet but my son does. I see my daughter is scared to walk she is not ready as of yet. Please advice are they developing okay or should I do something