The baby keeps on developing physically and mentally. Your baby can hold her head up well when propped to sit.
Introducing Your Baby To Solid Foods Center City Pediatrics
If your baby isnt willing to open up for an empty spoon hes not ready to sample solid fare. I dont see how people can wait so long to give their baby solid food.

Is My Baby Ready For Solids How Should I Introduce Them The Milk Meg
Is your baby mouthing his or her hands or toys. Can your baby hold his or her head in a steady upright position.

Signs That Your Baby Is Ready For Solid Food Baby Emma S Diary