For normal education, the doctor will suggestion baby to have solid food after 5 months. But it's depend on baby's growth progress.
Don't force you baby when she is not ready for the solid food.
Don't be afraid that she will lag behind the others.
For my gal, when she was 6 months old, the nurse said that her finger muscle was week, her also failed to sit better and have to mother clinic at 9 months old for re-assesement.
As I was in Shanghai at my gal's 9 months old and I didn't go to mother clinic.
When my gal was 12 months old, the nurse said that her fingers were very nimble cos she could pick up a very tiny biscuit which not many babies could do!