Shocked celebrity on time went first (8)
I believe the answer is:
startled
'shocked' is the definition.
(startling is a kind of shocking)
'celebrity on time went first' is the wordplay.
'celebrity' becomes 'star' (a star is a celebrity or famous person).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'time' becomes 't' (abbreviation).
'went first' becomes 'led' (I've seen this in another clue).
'star'+'t'+'led'='STARTLED'
(Other definitions for startled that I've seen before include "Stunned, shocked" , "Scared" , "Shocked, alarmed" , "Affrighted" , "Taken by surprise" .)