It depends. There is an enormous variety in what a deferral is and what it means - even from court to court in the same state - that the only person who can really answer whether the deferral in your case is a conviction is your lawyer. I've seen in both ways.

If possible, your attorney should consult briefly with an aviation lawyer. Sometimes lawyers in the criminal process don't understand the career consequence. Sometimes a "great deal" from a criminal law perspective can be a "bad deal" from an aviation one. And vice versa.