Young person playing with rattles (7)
I believe the answer is:
starlet
'young person' is the definition.
'starlet' can be an answer for 'person' (starlet is a kind of person). I am unsure of the 'young' bit.
'playing with rattles' is the wordplay.
'rattles' anagrams to 'STARLET'.
Though, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for starlet that I've seen before include "Young film actress with a future?" , "young celebrity" , "Promising young film actress" .)