Try searching 1772 to 1794: some children were baptised at ages older than infancy. One of my Carmarthenshire branches had all their children baptised in one batch, aged from infancy to late teens; I have a number of other Carmarthenshire examples of baptisms of smaller sub-groups of children with a lesser age range than that extreme example but still with some being baptised in their teens.

I have no feel for what period patronymics gave way to settled surnames in this part of Pembrokeshire but you might possibly be back to a period when it is a factor to consider?