Leadership can counsel you for anything. However in the situation you describe as long as:
- Your current uniform is authorized for wear
- Your current uniform is serviceable
- The mandatory possession date for the new uniform is not in effect
Then it would not be (in my opinion) professional for your leadership to counsel you. However this does not prevent them from counseling you.
Items for Consideration
If you are counseled for this you might consider simply disagreeing with the counseling statement and write your explanation concerning the mandatory possession date. Be calm, professional, and factual.
Another option is to consider why you are being asked to purchase the uniform. Is it because there is a special event coming up and the unit wants all personnel in the same uniform? Then perhaps you should consider purchasing the uniform as long as it does not put you in a financial hardship.