I was able to understand it roughly around when I entered my teens, in part because he was transferred to another country, where the embassy was a lot smaller and the country more insular, so it was common to get kids involved in embassy stuff to get the otherwise lacking sense of community.
It's hard to say if I would've been a diplomat if I had known earlier. I feel like being a diplomat is harder to innocently romanticize and turn into hobbies for a child in the way that 'scientist' can be.