I always figured Barnabas to be on the far side of his thirties. Sarah was ten. It seemed like a stretch, but by crunching the numbers the math can work. It's quite possible that Naomi was around 15 or so when she and Joshua tied the knot. That was common back then. And then, many years later, along came Sarah. Perhaps Naomi was very fanatical about taking her vitamins.
As for who was older, Edward or Judith, my vote goes with Judith, by a coupla years. Edward was always referred to as the oldest SON, not necessarily the oldest CHILD. That's the way it was back then, too. In the sexist Victorian society, the boys usually got the main course, the girls ending up with the leftovers. It still works that way in determining the line of heirs to the British throne. The oldest sons get first grabs, even if they have older sisters. Elizabeth is Queen only because her parents had no boys.
Gerard