Girl whose age is beyond five (4)
I believe the answer is:
vera
'girl' is the definition.
'age is beyond five' is the wordplay.
'age' becomes 'era' (I've seen this before**).
'is beyond' says to put letters next to each other.
'five' becomes 'v' (roman numeral).
'era' put after 'v' is 'VERA'.
'whose' acts as a link.
(Other definitions for vera that I've seen before include "Dame -- Lynn, singer" , "& 16 'The Forces' Sweetheart'" , "senior songstress?" , "Girl's name (meaning faith or true)" , "Duckworth, Lynn" .)