Firstly Mary Liz, let me tell you how blessed you are to have a son who's intelligent (I don't think I even knew what a Beatific Vision was at age 10) and who's obviously curious about Jesus (that's a bigger blessing!!).
The Catholic Encyclopedia defines a Beatific Vision as such:
The immediate knowledge of God which the angelic spirits and the souls of the just enjoy in Heaven. It is called "vision" to distinguish it from the mediate knowledge of God which the human mind may attain in the present life. And since in beholding God face to face the created intelligence finds perfect happiness, the vision is termed "beatific".
(Seeker you did pretty well on the definition, even though you hadn't read up on the official answers!)
Mary Liz, do allow me to copy & paste this from the encyclopedia regarding the
Knowledge of Jesus Christ1) The Beatific Vision
Petavius (De Incarnatione, I, xii, c. 4) maintains that there is no controversy among theologians, or even among Christians, as to the fact that the soul of Jesus Christ was endowed with the beatific vision (see HEAVEN) from the beginning of its existence. He knew God immediately in His essence, or, in other words, beheld Him face to face as the blessed in heaven. The great theologians freely grant that this doctrine is not stated in so many words in the books of Sacred Scripture, nor even in the writing of the early Fathers; but recent masters in theology do not hesitate to consider the contrary opinion as rash, though it was upheld by the pretended Catholic school of Günther. The basis for the privilege of the beatific vision enjoyed by the human soul of Christ is its Hypostatic Union with the Word. This union implies a plenitude of grace and of gifts in both intellect and will. Such a fullness does not exist without the beatific vision. Again, by virtue of the Hypostatic Union the human nature of Christ is assumed into a unity of Divine person; it does not appear how such a soul could at the same time remain, like ordinary human beings, destitute of the vision of God to which they hope to attain only after their stay on earth is over. Once more, by virtue of the Hypostatic Union, Jesus, even as man, was the natural son of God, not a merely adoptive child; now, it would not be right to debar a deserving son from seeing the face of his father, an incongruity that would have taken place in the case of Christ, if His soul had been bereft of the beatific vision. And all these reasons show that the human soul of Christ must have seen God face to face from the very first moment of its creation.
Though Scripture does not state in explicit terms that Jesus was favoured with the beatific vision, still it contains passages that imply this privilege: Jesus speaks as an eyewitness of things Divine (John, iii, 11, sqq.; I, 18; I, 31 sq.); any knowledge of God inferior to immediate vision is imperfect and unworthy of Christ (I Cor., xiii, 9-12); Jesus repeatedly asserts that He knows the Father and is known by Him, that He knows what the Father knows. There is a difficulty in reconciling Christ's sufferings and surpassing great sorrow with the beatitude implied in His beatific vision. But if the Word could be united with the human nature of Christ without allowing Its glory to overflow into His sacred body, the happiness of the beatific vision too might be in the human soul of our Lord without overflowing into and absorbing His lower faculties, so that He might feel the pangs of sorrow and suffering. The same faculty may be simultaneously affected by sorrow and joy, resulting from the perception of different objects (cf. St. Thom., III, Q. xiii, a. 5, ad 3; St. Bonav., in III, dist. xvi, a. 2, q. 2); the martyrs have often testified to the ecstatic happiness with which God filled their souls, at the very time that their bodies were suffering the extremity of torment.
Though it will take you a while to go through the passage the line that stands out is
all these reasons show that the human soul of Christ must have seen God face to face from the very first moment of its creation.Also it is the stand that the Catholic Church takes as well. In 1943 Pope Pius XII declared in an encyclical letter
MYSTICI CORPORIS CHRISTI (On the Mystical Body of Christ) that
"Jesus enjoyed the beatific vision "from the time He was received into the womb of the Mother of God." consequently, "the loving knowledge with which the divine Redeemer has pursued us from the first moment of His incarnation is such as completely to surpass all the searching of the human mind."
Hope this answers your son's question!
Blessings,
Melody
PS: Excuse my ignorance, but what does the 'AMDG' in your signature stand for?