Can I change my mind and leave if I feel it is not my calling?
Determining if you are called to this life is the purpose of the first year and a half. Should you determine that monastic life is not your calling, you are free to leave. After one makes vows, however, a dispensation is needed in order to leave.
Do I have to become a priest?
No. In fact, the first monasteries had no priests. Community members all take vows as Benedictine monks. Some chose also to be ordained to the priesthood.
I know the Abbey runs a seminary college. I wouldn't be interested in teaching.
Some of the monks do work in the seminary college, our oldest ministry. But the opportunities for other ministries are numerous: parish priest, monastery administration, woodworking, to name only a few. All talents, skills, and interests are welcome and can be used.