I've been friends with bi-curious women and had met some lesbian couples too, they seemed nice people, and I'd never thought that they should ever have been anxious about their orientation.
However I think many people (NT and Aspies) would be highy self-consious about finding out that they are "not straight" if there is a fad at their school which goes against those feelings.
You mention a good point about "everyone is carrying bags about with topless men on the cover". Then you mention "I have no feelings towards this".
The more interesting thing is that as an aspie, one tends not to follow the herd-menality.
Out of those many "normal" girls who carry bags with topless guys on them, some of those may well be bi or lesbian also, but as NTs they want to wear "straight looking bags & clothes" in order to fit-in socially.
So in summary, physical and personal feelings on ones own sexual orientation, no difference between aspies and NTs. But feelings about fitting into the 'herd' , that's something that the NTs do better with blending in with the crowd, and aspies would choose not to do so (hence the anxiety).