This is a Flow Size 5 nipple, designed for babies 6 months and older, and is suitable for your 1.2-year-old child if they feed comfortably. While age guidelines are helpful, the correct size depends on your baby's feeding speed and comfort. If your baby drinks easily without fussing or choking, Flow Size 5 is appropriate; however, if they get frustrated or suck too hard, they may require a faster flow.