Adult female holding on so soon (7)
I believe the answer is:
already
'so soon' is the definition.
(I've seen this before)
'adult female holding on' is the wordplay.
'adult female holding' becomes 'al' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on' becomes 'ready' ('ready' can be a synonym of 'on').
'al'+'ready'='ALREADY'
Can you help me to learn more?
(Other definitions for already that I've seen before include "By the time in question" , "Even this soon" , "thus far" , "Indication of impatience (US)" , "Previously" .)