Complex sentence: Sister Thérèse hoped to make her final commitment on or after 11 January 1890-but, considered still too young for a final commitment, her profession was postponed; she would spend eight months longer than the standard year as an unprofessed novice.
Split into simpler sentences: Sister Thérèse hoped to make her final commitment on or after January 11,1890 but, considered still too young for a final commitment, her profession was postponed. She would spend eight months longer than the standard year as an unprofessed novice.