Kids are different but at 18 months she should be able to eat anything you are eating not just soft, mushy foods. My oldest had a major gag reflex on chunky foods, though, so even at 18 months she would still gag and choke on them. It was a major pain in the butt but she grew out of it.
My other kids never had those problems. My youngest was self feeding herself when she was 7/8 months old. She fed herself Thanksgiving dinner when she was 7 1/2 months old (turkey cut into tiny chunks, potatoes, sweet potatoes and broccoli). By Christmas she was completely self fed and eating whatever we had within reason (she was 8 1/2 months).
You just keep offering it. Put it on her plate but don't feed her. She will eat if she is hungry.
at 9:16 AM on May. 15, 2009