The youngster's in luck, I dare say (3)
I believe the answer is:
kid
'the youngster's' is the definition.
('kid' can be a synonym of 'youngster')
'in luck i dare say' is the wordplay.
'in' indicates the answer is hidden within the clue.
'KID' can be found hidden inside 'luck i dare say'.
(Other definitions for kid that I've seen before include "Playfully deceive" , "little one" , "Deceive - child" , "Soft leather" , "A baby goat or informal child" .)