This is normal sometimes there can be a slight delay . We need to take care of the teeth which are there .you should start brushing them with a finger tooth brush or a ultra soft "kids tooth brush "and very little smear size tooth paste or a thin layer of tooth paste of the size of rice grain .we have to brush those teeth two times a day .

Hey don't worry rest of the teeth will come gradually.. give dal khichdi with vegies... Mashed potatoes n other things too..