developmental challenges for late term babies?

my DS came last Aug 5 at 4am. I was 35 weeks and 4 days pregnant and had contractions since 35w2d, was given a shot of steroid for baby's lungs in case he comes early, put on magnesium for 24 hrs to stop the contractions so steroid shot can take effect. He was 5lbs 11oz when he came and 18 inches long, was taken to NICU but never put on an incubator, taken off the heater the same day because he can already hold his temperature, blood sugar was very good, was able to bottle feed with no problems, blood work all came negative for infection, bilirubin level was low and passed every screening test. is there a chance that he will encounter developmental challenges when he grows older even if he did great with all his tests at NICU and did not have any of the problems most preemie have?