Why do people obsess over my daughter's development? at 4 months what thing do you expect from your baby?

I don't know what Sentenna's problem is? But yeah I have a friend, her son is 4 months and he can stand up when he is holding onto something. A lot of babies are advanced, my daughter 3 1/2 month old daughter is too. I think you daughter is developing just fine! She will be sitting up sooner or later :)