One thing I remember most vividly from my childhood as I get into anti-oppression and disability rights politics is the amount of internalized ableism I and others I knew had.
I’ll illustrate with two stories:
When I was a kid I developed a very hierarchical view of intellect, with academic abilities corresponding to one’s worth. While I have autism, I also have above average academic aptitudes. However, special ed students generally are considered less intelligent and less academically capable. So I actively attempted to hide that I was in special ed, distance myself from my friends in special ed programs, etc. This is what internalized ableism looks like.
I also went to a summer camp for kids with sensory integration difficulties. Most of us were “high functioning” autistic types, and not really visibly disabled. Those who were more obviously disabled (those who had speech impediments, speech delays, learning delays, etc.) almost always ended up bullied by the other kids, although the camp counselors tried to stop that bullying. This is what internalized ableism looks like.