With no way of proving age, is not taken out (7)
I believe the answer is:
undated
'with no way of proving age' is the definition.
I can't tell whether this defines the answer.
'not taken out' is the wordplay.
'not' becomes 'un' (prefix meaning 'not').
'taken out' becomes 'dated' (I've seen this in other clues).
'un'+'dated'='UNDATED'
'is' is the link.
Can you help me to learn more?
(Other definitions for undated that I've seen before include "Not marked with day, month, year" , "open" , "Lacking DDMMYY" , "not having the time?" .)