As God wills.  But age 14 today is not as it was a century ago.  Up until WW I, age 14 was when the majority of American young men left school for full-time employment.  Try that today and  Mom and Dad will lose their child to CPS.  Like it or not, the U.S. govt. considers childhood to end at 26 under Obamacare.  This is not to say the boy of whom you speak hasn't a vocation.  Even if he does, it's most unlikely he'll be ordained at 19 or 20.  How many today are mature enough to function as adults when still in their teens?  Maybe I'm too pessimistic?

 :rahrah: or  :geezer:?
Up until about 1900, age 14 was the age at which one was expected to be able to put in a full day's work in the U.S.  That meant 12-14 hours, six days per week, not eight hours, five days per week.  If you were old enough to work, then you were old enough for the convent, monastery or seminary.  There was nothing magic about the age.  Society expected mature behavior much earlier.  Youth was not yet considered the ideal.  Today, it has become an idol.  As Bishop Williamson said, "The elderly are not respected unless they put on jeans and sneakers and pretend to be teenagers."

I think it is good age because there would be less exposure to the world.  About that age many should know what they want to do.  

What was special about age 14 that 'many' boys and girls entered seminary/convent?

It occurred to me that it corresponds to the customary age for completion of school grade 8.  Before Vatican II, that was the final grade in Catholic parochial (i.e.: parish) schools.

The Council of Trent established the rules for seminaries and their students:

Let those be received [....] who having been born in lawful wedlock, have at least attained their 12th year, are able to read and write passably, and whose naturally good disposition gives token that they will always continue in the service of the Church." (1563, 23rd Sess.)

[....] Today an ordinary grammar school instruction is required for admission into the preparatory seminaries. [....]  Parents and parish priests are urged to encourage and to help boys who by their intelligence and piety give hope that they are called to the priesthood (Council of Baltimore, no. 136).

Thus, successful completion of the 8th grade (Q.E.D.).  Perhaps a rule-of-thumb had evolved that trying to evaluate intelligence and development of learned skills, before completion of the 8th grade, risked overlooking late bloomers who'd develop into perfectly satisfactory priests.

For a boy with a probable vocation to the priesthood at the outset of the 20th century, a common U.S. path would've been 6 years of preparatory (i.e.: petit) seminary, and if he could've passed the entrance exam, 6 years of theological (i.e.: grand) seminary.  For centuries, there'd been other options for study (e.g.: in Rome), but absent a dispensation by the applicable bishop, successful completion of those 12 years of seminary training seems to've been the shortest U.S. path to ordination to the priesthood.

Our moderator and some regulars here are reputed to have studied at seminaries, so I solicit corrections.

:surprised:
Sorry, Alligator!  That was supposed to be a thumbs up!  Good research!  An eighth grade education was once what is now becoming a four-year college degree.  

I gave him a thumbs up for you  :smile:

Marsha