How often do girls who once identified as straight but now identify as lesbian go back to identifying as being straight?

Usually when people identify as homosexual, this is their actual sexuality and has been for a long time. Homosexuals face a lot of challenges, so most usually when they choose to come out, they are revealing who they actually are. The "straight" identity was the false one and you are now seeing who they really are, so they will never return to wearing the mask.

The very rare exception to this is someone who is bisexual and who will always be bisexual, but who chooses to call herself straight at some point after making the decision to only sleep with men despite her continued attraction to both genders.