I encounter this problem everyday with my 4YO gifted, sensory seeker. He is so excited about whatever topic of the week he is interested in. He always wants to share his knowledge with someone and adults will dismiss his interest and not really listen and respond with a confusing to him response. For example, one week, he was into the life cycle of Sea horses and carried a chart around with him. He showed it to someone and they said, "oh, you have been to the aquarium?" "Did you have fun?" He tries a couple of more times and then either shuts down and gets quiet or goes the silly route.
What do you say to people? Do you have something to say to explain sure he looks like a 4YO but his MA is 7-8YO? As far as support professionals go, I will keep searching until I have the right fit. Gifted kids are too sensitive and too observant to read the faces and know when people are not really interested.