I knew a girl in school who had severe arthritis and was in a wheelchair because of it. We were friends from when I was 8 until I was 18 and then I had DD1 and she doesn't like babies so we stopped being friends.
Then there is Andy and BIL (and previously also FIL when he was alive), who had HMSN type 1a, but they are literally the only disabled people I've ever met - no one with CP except me.
My primary (I think you call it elementry?) school had only 70 students in it, of which only me and BIL were disabled students there, and at high school there were 500 students - with only me and the girl with arthritis having a disability.
No, my mother isn't the kind of woman who would ever join me to any advocacy groups because she's prejudiced and doesn't think I deserve the same rights to normal life as others anyway. She told me that me and Andy should have been 'sterilized at birth', and that 'disabled people shouldn't have children.'
Even on my wedding day, she said to me that she was so happy because she thought that with me being disabled, no one would ever want me. Honestly, those were her exact words, ON MY WEDDING DAY!!!
I have never met another adult with it, no. Although when I was 19 I did do a temp job in an office (answering the phone and such) for Scope, which is the charity for people with CP. All the other office workers were able-bodied, though. I have phoned their helpline once when I had housing problems and I got legal advice from the Disabled Parents Network when I was going through court, but that is the only time I have ever thought about it.
Most of the time I don't think of the CP unless something happens because of it or one of my kids asks me about it (they question me quite a lot on the subject, even DD4, who is only 3).