I pointed out such children to my DD when she was small-- though she had already noted that bragging in this way (especially unsolicited) made others feel resentful and that nothing good came of it, socially speaking.
We discussed that "for my age" is really not a reasonable benchmark when you are unusual, anyway. And besides, "I was the best reader in my kindergarten class" sure isn't something you hear teens or adults mentioning off-hand... wonder why that is...
I consider this kind of thing a good opening to teach about social nuances and how we portray our authentic selves to the world at large. Being "true" to that self can also mean being quiet-- if part of your identity is "a person that others find comfortable and pleasant to be with."
