I wouldn't worry too much about any of it. If you don't want to listen to her talk for so long about herself/her kid, bring something else to do for distraction and to make it look like you're obviously not into talking/listening.
As for the content - if the school situation is as you describe, the kid is probably a relative genius in the school. The Google says the average IQ of an MIT student is 140, so 130 is not beyond the pale; likely the kid will end up somewhere else, but what the hey. When I was 12 I planned to be an astronaut.
The autism comment doesn't strike me as all that offensive. Autistic kids are weird, for the most part. That's often how you realize they might be on the spectrum, right? It's not meant (likely, unless you saw something in her tone that was exceptional) as any more pejorative than speaking frankly/casually normally is.