I started cooking soft rice for my son about two months ago, as he didn't like congee as before.
I steam two to three types of vegetables plus one type of minced meat. Then serve with rice, he can finish one big bowl (rice with veg and meat) each time. He can chew well and he has ten teeth already. His poo poo is okay, of course not as soft as before.
You can try, no need to struggle. I think his appetite and preference will tell you if he's ready for rice or not.
For veg - I wil give him different types of leafy veg, gourd, onion, pumkin, celery, carrot, peas, tomato, eggplant, sweet potato, etc
For meat - pork, beef, chicken, salmon/cod - sometimes mix with cheese, beancurd or egg.