The birth was the only thing that happened.in.the future. Try again.
Behold, you will conceive in your womb and bear a son, and you shall name him Jesus.
Gabriel speaks of the conception, birth and the naming all as a future event. What isn’t said is you are conceiving right now. It is all future. Mary was married. She doesn’t say “I don’t live with Joseph” She doesn’t even speak about Joseph, Gabriel does not give a time frame of when it will happen other than it will be a future event.
What you have been unable to refute is that it is future. Mary was married. It is not germane that she wasn’t presently living with Joseph as she expected to live with Joseph. She would have understood that Gabriel spoke about a future event. IF she had planned on a normal life with Joseph she would not of asked that question.
One other point is that you say you believe she remained a virgin and yet you don’t have a good explanation as to why she would have other than the vague “Mary and Joseph can simply decide to dedicate their lives to solely raising Jesus.”
I am still looking for proof that they had to remain “pure” for a year. It was not in the link you provided.