Although it is considered acceptable to ask a transgender girl whether she is normal before or after surgery, this is not the case. Once you know her, she might let you know; No one wants to date someone who is no longer interested once their privacy is compromised. If you're worried about wasting your effort, say in a very tactful way that you're only interested in it and then give it up. If your transgender female is not the kind of person you're talking about, she's likely to politely decline your further invitation to spare you the effort.