Yes, you are right, here a boy is an immature, so it can be deems somewhat as an animal, so I used "it", and when I found it's necessary to make the personal prons clear, I would use "he" instead of "it".
But anyway, you should unify the use of he or it.
But as is noted, the French text is also mixed with HE, It, They, sometimes you see, it speak once in "s/he", "his/her" and then in "they", "their"::
)
Just understanding.
By the way, you are like scientist!!