is used when referring to a specific individual already mentioned or known: " The pretty rose shemale arrived at the event."
However, please note that the term "shemale" is widely considered a when used to describe transgender people outside of specific adult industry contexts. In respectful or formal conversation, the appropriate and "proper" way to refer to such an individual is as a transgender woman (e.g., "a pretty transgender woman" ). pretty rose shemale
The proper article for the phrase depends on the context of the sentence: is used when referring to a specific individual
is used when referring to one unspecified individual: "He met a pretty rose shemale." pretty rose shemale