it says "his legitimate wife" after her name. (in Italian -"sua moglie legittima"
"come sopra" is used like the word "ditto" in English. Instead of repeating information that was previously written in the record, it says "as above." So, his age of 31 is given for him in the record. When it comes to her age, it says "as above" meaning she is the same age as her husband.
Actually her age of trentuno is given in the record. Where it says, as above, it is referring to information about her husband that was already given in the record. So his profession of contadino was given with his name when he appeared at the town hall as the informant in the record. But then when the record talks about the child being born from his her, his legitimate wife, and from him, the informant, instead of repeating his age and occupation, the document reads "as above."