Call a Navy Recruiter or you local Navy Reserve Center. Unless you make LDO as a resevist, I think your missing the college degree that is required to become an officer.
Navy Reserve Merchant Marine Officers
Merchant Marine officers in the Navy Reserve are professionally licensed deck, engineering and radio officers employed in the maritime industry. The Merchant Marine program is composed of a corps of actively sailing officers who serve on naval vessels in time of war or national emergencies. Additionally, these officers serve as shoreside cadre assigned to Navy Reserve activities in support of sealift readiness, namely the Military Sealift Command (MSC).
Basic Education Requirements
Graduation from the U.S. Merchant Marine Academy, a state maritime academy or an accredited industry school, and successful completion of the prescribed course in naval science. Most graduates will typically be offered a Navy Commission in the Individual Ready Reserve. Accept it, as it will otherwise be difficult to obtain later. With this commission, it is practically effortless to affiliate with a Selected Reserve unit, should you choose to do so.
At least 19 but less than 40 at time of appointment. This age maximum can be waived up to 42, with prior military service.