Autism or prematurity?

My son was born premature at 33w. He weighed 2lbs 15oz. He is 15 months adjusted now. He has been behind a little behind with his adjusted milestones and some are concerning me. He can cruise but not walk. He can say giberish but not babble (Mamama,dadada,bababa, etc). He says mama only when he cries( not sure if he knows). He won't eat table food only baby food( I try table food every meal several times before I give up). Doesn't point but this can come as late as 18 months. Won't look at me when I call his name multiple times ( he can hear because if we make noises he looks). Ignores me really. He can maintain eye contact for a bit before he looks away. Halfway looks where you point. Doesn't mimic us. Isn't afraid of strangers. I will be talking to his doctor at his 18- month check-up about his development. His doctor also said if he wasn't walking ,talking, or eating table foods by then he will be going to therapy for all 3.