There is evidence now that one can achieve a greater immune response by receiving the second jab after 3 months and that this approach might make a third booster unnecessary. We are in one grand experiment after all so expect evolving advice.
verywellhealth.com/delaying...
As far as vaccinations for children and for boys in particular, I just heard an infectious disease physician from John’s Hopkins say that the hospitalizations of boys for myocarditis is six times that of their hospitalizations for COVID. So to mandate this group be vaccinated is imprudent. By the way, this same doctor also said that he himself received his second jab after 3 months and has experienced a strong and so far comparatively durable response.