Ad-Jesum-per-Mariam:
If you are already commissioned in the Army Reserve, you may be able to become a seminarian. The Archdiocese for the Military Services does have a co-sponsorship program. Besides, since you are already serving, time towards service is counted, and the Catholics serving in the Army will probably respect you more, since you have served in a different capacity within the Armed Forces.
You would have to ask the vocations director for the Priestly Fraternity of St. Peter. If no, I’m sure some diocesan vocation directors (i.e. Wichita, Lincoln and a few others) would be open to someone like you. Priests serving in the Armed Forces are through the Archdiocese for the Military Services, but they are ordained for either a diocese or a religious order, and have permission to serve in the military (and must pass physical requirements and other criteria) from either their diocesan bishop (or archbishop) or their religious superior.
Recently, three priests from the Ordinariate for the Chair of St. Peter (who have prior military chaplain service) were granted permission to serve as Catholic priests in the military.
Good luck!