Baptism, in scripture, as promoted by Christ and the Apostles, is clearly an individual choice made by persons who understand what they are doing... not a reward, but an act of faith.
And parents make the decision on behalf of their children to have them baptized. Thank God for that. We make the decision to bring them to the doctor or should we wait for our 3 month old to tell us to bring them to the doctor.
I seem to recall in scripture that many “households” would be baptized at the same time. I’m sure there were children in those households.