"You're transgendered, aren't you?"
That's almost like asking someone if they had cancer when they were young. Or were abused as a child. Why yes, I was trans, thank you for bringing up such a painful subject. Why don't you give me a paper cut and pour lemon juice on it or something.
Why is the answer going to be useful to you? Examine your reasons for asking, especially as one of the first questions you ask me.
Does it help you understand me better? No it doesn't, if you've met one trans person... you've met ONE trans person. Despite our shared affliction, we are probably nothing alike.
Maybe you want to tell me that I'm obviously trans. That's lovely. No wait, it is horrible.
Are you concerned I have the wrong bits? If I feel that will be something you would need to know, I'll tell you when I feel comfortable doing so (and before it is an issue).
Is it wrong of me to want you to see me as a woman first to maybe help break a few stereotypes you might have?
