NTA regardless of what you choose to do

But I would suggest waiting and seeing if it happens again

You communicated your boundary. As of now, it has not happened again.

If it does happen again, then I would suggest taking this up with HR and management. Because then there would be two instances and they would not be able to pass this off as a one time occurrence.

See, this isn't a matter of you not liking being touched because you are on the spectrum. That really doesn't matter at all in the world of corporate HR.

Employees walk a fine line when they touch other employees. It can often be misconstrued as unwanted sexual attention or harassment...which is why most companies make their employees well aware that they should not be touching anyone because of the liability it creates.

This was not a pat on the back or a high five.

If you were a dude or she was a woman interested in other women...this kind of touching would be immediately flagged by HR as unwanted sexual attention.

Which is why companies tell each other not to do things like this because sexual harassment and hostile work environment issues get really messy for companies.

Me personally, I would document the incident. Time, place, exactly what happened.

And then see if it happens again.

If it doesn't. Great. She understood your boundary and respected it.

If it does, or if she gives you attitude about it...then go directly to HR. You tell them about the first incident, how you communicated you didn't want her touching you like that...and that it happened again...and that you would like HR or management to intervene