Age for a quinceañera (7)
I believe the answer is:
fifteen
'age for a quinceanera' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for fifteen that I've seen before include "Rugby Union team" , "Square root of two hundred and twenty-five" , "Film type" , "Square root of 225" , "Product of two primes" .)