Shy if daughter started in deft performance (9)
I believe the answer is:
diffident
'shy' is the definition.
(I know that shy can be written as diffident)
'if daughter started in deft performance' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'started' says to put letters next to each other.
'performance' indicates anagramming the letters.
'in'+'deft'='indeft'
'indeft' anagrammed gives 'fident'.
'if' put after 'd' is 'dif'.
'dif'+'fident'='DIFFIDENT'
(Other definitions for diffident that I've seen before include "Timid" , "Bashful" , "Reluctant to come forward" , "Shy" , "Lacking self-confidence" .)