I may be wrong,and willing to stand corrected, but nowhere in that link does it refer to a person under 21 as being "a minor".
Certainly, as I already stated previously, permission to marry from the age of 14 years (for a boy)to the age of majority being 21yrs, was required. (I too required my parents permission at 18 years in 1965.)
However, the words "a minor" were added to the registration, if the person was under 18 years. As far as I am aware,(and certainly this was an issue in my own case as the law had not changed regarding this)