Often rue going wild at this age (8)
I believe the answer is:
fourteen
'this age' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'often rue going wild' is the wordplay.
'going wild' indicates an anagram.
'often'+'rue'='oftenrue'
'oftenrue' is an anagram of 'FOURTEEN'.
'at' is the link.
Can you help me to learn more?
(Other definitions for fourteen that I've seen before include "Pounds in a stone?" , "XIV" , "Fen route (anag)" , "Number of lines in a sonnet" .)