Written by Navjote and Christian confirmation look surprisingly familiar when they are placed side by side. That makes them worth comparing. It does not make them the same rite.
What navjote actually does
Among Parsis, navjote formally brings a child into responsible Zoroastrian religious life through investiture with the sacred shirt and cord. Iranian Zoroastrians preserve the related sedra-pušun. The ceremony joins prayer, religious identity, moral responsibility, and the wearing of sacred garments.
That is a powerful initiation structure, and the sacred cord itself has deep roots in Zoroastrian tradition. But the complete modern ceremony should not simply be pushed backward unchanged into the second millennium BCE. Rituals have histories too.
Christian confirmation took another route
Early Christian initiation commonly joined baptism, anointing or laying on of hands, and admission to the eucharistic community. Over time, especially in the West, parts of that initiation sequence separated. Post-baptismal anointing and episcopal laying on of hands eventually developed into what later Christians recognized as confirmation.
So there is already a documented internal Christian history for the rite. That does not make comparison with navjote pointless. It means a claim of direct borrowing needs evidence strong enough to overcome that internal explanation.
What would make the case stronger?
We would want more than the fact that both traditions initiate young people. We would need a plausible community or institution through which the specific Iranian rite moved, distinctive shared features that are unlikely to be generic rites of passage, and some sign that Christian practice changed after that contact.
Right now, the resemblance is interesting but the direction of dependence remains open.
That is still worth saying. Zoroastrianism preserves an ancient initiation tradition centered on sacred clothing, prayer, responsibility, and communal identity. Christianity developed its own initiation complex and eventually separated confirmation from baptism in parts of the church. Put them beside each other and the comparison is real. Call one a proven copy of the other, and the evidence starts to thin out.