Unfortunately, there are Catholic Resistance members who go by the 1917 Code of Canon Law when it comes to the beginning age regarding the Church’s law on fasting. The 1917 Code states that those who have attained the age of 21 must fast on the obligatory days. However, the 1983 Code is more strict in this regard. It states that the beginning age is when one has attained the age of majority. See Canon 1252 here. In Canada and the United States the age of majority is 18. Therefore, one who is 18, 19, or 20 years of age in Canada or the United States cannot go by the 1917 Code. They were obliged to fast under pain of mortal sin on Ash Wednesday and are obliged the same on Good Friday. Those of the Catholic Resistance who say otherwise need to be questioned whether they accept Pope John Paul II, who promulgated the 1983 Code, as a true pope. If they do, then they need to explain why they say otherwise because the beginning age of fasting stated in Canon 1252 is not in opposition to Faith or Morals.