I can understand her comments about you rubbing your hands and rocking on the stool because bodily posture and relaxation are relevant to playing the piano. I do find it a bit, no very, strange that she should comment on how you dress. I don't wear high heels and I would find it extremely inappropriate for anyone to comment that I should. But maybe I'm just misinterpreting the conversation.
On the issue of her being likely to have come across other Aspies, or being one herself because she is a musician, I think there is more than likely something in that.
A few months ago I heard a radio programme, which I missed the start of, in which a man had researched the impact of time spent practicing a musical instrument on eventual success. I think it was violinists he had studied. His point was that although innate talent is a factor, the key to success is drive. He calculated/observed that all successsful violinists had put in about 10,000 or was it 100,000 hours of practice. Can't remember the figure, but it was a LOT. Basically it equated to 10 years of dedication.
The woman interviewer commented that spending so much time practicing meant that those people wouldn't really "have a life". His point was that playing the violin "was their life".
At the time I remember thinking about this in terms of autistic obsessions. The ability to focus intently for lengthy periods of time on a specific subject or interest, be it music, engineering, architecture, whatever.
This doesn't mean to say that all violinists are autistic, but it does suggest that anyone who is prepared to devote their life to their own area of interest has at least that one "obsessive" trait in common with autistic people, and maybe more.