One’s advanced only so far (6,5)
I believe the answer is:
credit limit
'advanced only so far' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'one's' is the wordplay.
I cannot really see how this works, but
'one's' could be 'im' ('one is' is a formal way of saying 'I am') and 'im' is found within the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for credit limit that I've seen before include "Maximum level for borrowing" , "Maximum sum allowed for drawing from bank" .)