I believe the correct answer is naive. The author is trying to say that he was ignorant, and that he couldn't understand properly these new revelations. He was either too young or too stupid to understand such a thing, but he believes he will as he grows older.
<span>Naive. The author is explaining that her wonder was from a new discovery, immaturity derived from her youth, something that would be better understood by her later in life.</span>
