I admire your point. However, it must be remembered that Katherine and Arthur were essentially children who had been cossetted and sheltered all of their lives. How in the world, at the age of 15, could Katherine possibly understand "consummation" of the marriage? How could Arthur? It must be remembered that Arthur called for wine the next day, saying "Marriage is thirsty work, and I have been deep in Spain." Did he know what he was babbling about? I doubt it. At that age, perhaps kissing and heavy ...ehem...playing around were "consummation" to the young couple.
The average life expectancy at birth during Tudor times, was 35 years. If a child lived into their mid-teens, they could reasonably be expected to live to their 40s or 50s.. although women usually died younger than men, since they bore the children and their risk of death was much higher.
It is a mistake to view life in medieval Europe through 21st century eyes, because though today we consider a 14 or 15 year old as being still somewhat a child.. in the 15th and 16th centuries that was not the case. Most girls were already mothers by the age of 15, having lived almost half their life expectancy by that time.
Catherine of Aragon would certainly have been aware of the meaning of marital consummation, just as she would have been taught about the court of her future husband and all the other aspects of education for a princess and future queen.
It was considered the duty of a mother to prepare her daughter(s) for marriage, including instruction on the facts of life. I can be virtually certain that Isabella of Castile would not shirk this duty with any of her daughters.
After all, the goal of a political marriage was to unite two houses by blood, with the children or 'fruits' of the marriage cementing the familial relationship and political alliance.
Certainly after all the time and money invested in the negotiations of the betrothal and marriage contract, which could take years in the case of royal children, the sooner the couple performed their duty to beget heirs the better. No one would overlook telling them how that was to be achieved.
It is also the reason that medieval parents carefully timed when a couple would commence sexual relations - usually at the age of 12 for girls and 14 for boys - it was considered safe for them to fully co-habitate, though they could have been legally married for several years by the time they reached those respective ages.
In the case of Arthur of Wales, I have seen no evidence to suggest that he was a virgin when he formally married Catherine at the age of 15. In all likelihood, he was not inexperienced by then. But in any case, he too would have known the meaning of consummation and what was expected of him in fulfilling his marital duty. If he was unable or unwilling to bed his wife, he was still a young man.. who would never admit such a failure to his friends, to his companions or to his courtiers. As a prince he would never admit to a failure of his duty either.
Of the two, Arthur was probably more sheltered than Catherine. If it is true that he was not in good health and/or prone to illness, then he was more likely to have been over-protected by his parents. Catherine, on the other hand, was the daughter of two strong and vigorous parents, who rode into battle together on more than one occasion.. so she probably had more worldly experience than her young husband.
And there is definitely a difference between living a life of privilege, as the son or daughter of a monarch, and being cossetted and sheltered. Most medieval children were never cossetted, in any case; especially the children of the nobility or children of royal rank, who were rarely in the presence of their parents beyond babyhood. They tended to form closer bonds to their nannies, tutors and governesses, than to Mom and Dad.