Jack-Jack 6 Months Old

Our little baby boy is 6 months old already. At his check up, he weighed in at 19 lbs 11 oz (75%-80%) and 28.5" (90%). He is doing well and had a couple more shots. He has now started on peas and will have green beans soon. He sits up well and no matter how hard I try to get him to sleep on his back, he always flips over and sleeps on his tummy.