Don't be so edgy OP.
That said I do consider not revealing ones sex to a potential romantic partner until later on in a relationship to be a form of sexual assault. The vast majority of people are not bi, since even homosexuals can end up getting an unpleasant suprise in this department.
I think it probably would be hard to define it as rape that said, since once the clothes are starting to come off its fairly obvious what they really are. Potentially yes, but there are very few trannies/traps/ladyboys etc who have fully transitioned so well they can pass at that level.